Posters til Landsmøte i Kjemi

Det 21. Landsmøte i kjemi

Posters og Posterabstracts

Disse faggruppene har postere:

PU - Uorganisk kjemi og materialkjemi

Abstractene står under titlene

PK - Katalyse

PK1	Selective Oxidation of Methane to Methanol Over Cu-loaded SAPO-34 Catalysts Karoline Kvande (UiO)
PK2	Investigation of the effect of different activation conditions on the catalytic activity of Pt-functionalized UiO-67 Bjørn Gading Solemsli (UiO)
PK3	Influence of the pressure and the reaction flow regime on the conversion of methanol to aromatics. Irene Pinilla-Herrero (UiO)
PK4	The use of UiO-type MOFs in gas phase Soai reactions Giuseppe Rotunno (UiO)
PK5	A DFT study on the reaction mechanism of methane to methanol direct conversion via Cu-exchanged chabazite catalyst. Carlo Buono (UiO)
PK6	Bimetallic CuPt and CuPd nanoparticles prepared by Microwave Synthesis for CO 2 conversion to useful fuels. Maria Kalyva (UiO)
PK7	Real-time regeneration of a working zeolite monitored via operando space-resolved X-Ray diffraction. Georgios N. Kalantzopoulos (UiO)
PK8	Ethene dimerization with metal-organic framework (MOF) functionalized with Ni(II) and bipyridine. Mustafa Kømurcu (UiO)
PK9	Synthesis and characterization of gold(I) NHC complexes suitable as FEBID precursors. Cristiano Glessi (UiO)
PK10	Production of high surface area zirconium oxides through thermal metamorphosis of metal organic frameworks. Christopher W. Affolter (UiO)
PK11	Magnetic properties of [NpO₂(dpc)₂]^2- in solid and in solution. Julie Héron (UiO)
PK12	Biomimetic copper complexes for incorporation into MOFs Isabelle Gerz (UiO)
PK13	A Niobia-Supported Iridium-Based Catalyst for Deoxygenation of Lignin-Derived Model Compounds Simen Prang Følkner (UiB)

Abstracts

PK1

Selective Oxidation of Methane to Methanol Over Cu-loaded SAPO-34 Catalysts

Karoline Kvande

University of Oslo, Department of Chemistry, Sem Sælands vei 26, 0371 Oslo
karoline.kvande@kjemi.uio.no

Direct conversion of methane has had a lot of focus in research over the recent years, especially because of the increasing abundancy, and the following need for utilization. Today, methane is mainly converted to synthesis gas (syngas), which is a highly energy-intensive production. Syngas is further applied to produce useful products, such as methanol, hydrocarbons and NH3. Because of the costs, the industry often flares off the methane recovered as side-products instead of turning it into valuable products [1]. The need is therefore high to find alternative routes for the conversion of methane.

In this work, we have tested a Cu-incorporated silicoaluminophosphate, SAPO-34, as catalyst for a stepwise, cyclic route for the conversion of methane to methanol. The reaction route is based on an enzyme, mono-oxygenase, where zeolites, ion-exchanged with metals, are able to stabilize metal-oxo sites. The reaction has been tested on a wide range of zeolites before, such as MOR, CHA and MFI, and several of these have shown promising results [2].

To investigate the material, we have combined activity tests with a wide variety of characterization, such as elemental analysis with EDX, structure analysis with SEM and XRD and estimation of the pore size with BET. Interestingly we see that by going down in the methanol extraction temperature, the selectivity and productivity increase for the Cu-SAPO-34 materials (e.g. from 12 to 28% and 1.0 to 3.0 μmol/g). Further investigation and characterization is however necessary to determine the optimal conditions and the suitability of this material for the selective oxidation of methane to methanol.

Figure 1: “Giving methane wings”

References:

P. Tomkins et.al, Acc. Chem. Res. 2017, 50, 418-425
D. K. Pappas et.al, J. Am. Chem. Soc. 2017, 139, 14961-14975

PK2

Investigation of the effect of different activation conditions on the catalytic activity of Pt-functionalized UiO-67

Bjørn Gading Solemsli*, Emil Sebastian Gutterød, Unni Olsbye

Centre for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, Sem Sælandsvei 26, N-0315, Oslo, Norway
* – b.g.solemsli@kjemi.uio.no

Recent advances in the use of metal-organic frameworks within catalytic chemistry introduced a different ways to hydrogenate CO₂ using of functionalized UiO-67[1]. The goal of this project was to investigate the effect of different activation conditions on the catalytic activity of CO₂ hydrogenation over Pt-functionalized UiO-67 (10% bipyridine). Three activation variables were investigated: time, temperature and atmosphere composition. The CO₂ conversion, product selectivity and product yield was calculated based on the collected data. The standard activation conditions were one hour at 348 °C under flowing atmosphere of 10% H₂ in inert. The time variable was varied in range 0 to 6 hours, temperature variable in range 194 to 372 °C, and the hydrogen concentration in range 0 to 60%. Five different test for each variable were done except for the standard that were only done once. When one variable was changed the rest were standard activation conditions. The standard reaction conditions were 240 °C for 820 min with 10% CO₂, 60% H₂ and 30% inert (Ar with 10% Kr) with three different contact times:0.0066, 0.01 and 0.02 min g mL-1. The conversion increased as the activation time and the H₂ percentage in the activation atmosphere increased in an asymptotic manner. The conversion after 4h and 6h were roughly the same and activating in 20% H2 showed a lower conversion than the trend. When increasing the temperature the conversion seem to increase in an exponential manner until it gets to its peak at 4h. In conclusion, the activation temperature and the activation time have a greater impact on the conversion, while the atmosphere composition gives the same as long as there is an abundance of hydrogen (over 10% in the activation atmosphere).

Figure 1. Conversion as a function of each of the variable that was changed during activation. From left to right: ΔTemperature, ΔPercentage H₂ in the atmosphere and ΔTime. Reaction conditions: 233˚C, CO₂/H₂/Ar = 1:6:3. The solid line on is just a guide for the eye, not actual data.

Reference

Emil Sebastian Gutterød et al. CO2 hydrogenation over Pt-containing uio-67 Zr-MOFs—the base case. Industrial & Engineering Chemistry Research, 56(45):13206–13218, 2017.

PK3

Influence of the pressure and the reaction flow regime on the conversion of methanol to aromatics.

Irene Pinilla-Herrero^1,2*, U.V.Mentzel², F.Joensen², K.P. Lillerud¹, U. Olsbye¹, Stian Svelle¹, Pablo Beato²

1 – Department of Chemistry, University of Oslo, Blindern, Oslo 0315, Norway
2 – Haldor Topsøe, Kgs. Lyngby 2800, Denmark
* corresponding i.p.herrero@kjemi.uio.no

The transformation of methanol into aromatics (MTA) is an interesting alternative for the production of benzene, toluene and xylenes, which are currently obtained from naphtha. Zn-ZSM-5 materials are known for being active MTA catalysts, being able to favor dehydrogenation rather than hydrogen transfer reactions, thereby enhancing the selectivity to aromatics while keeping the production of alkanes low [1]. The exothermicity of the MTA transformation and the need for a continuous regeneration of the catalyst due to cooking, point towards the use of a fluidized bed reactor for the industrial implementation of the process.

In this work, we aim to study MTA at industrial relevant conditions and how the change in these conditions can alter the catalytic performance of the catalyst employed. To do that, a series of spherically shaped catalysts (containing ZSM-5 and alumina) have been tested at high pressures in fixed and fluidized bed reactors. In addition to that, the effect of the presence and amount of Zn in the shaped catalysts has been also investigated. Figure 1 shows a summary of the results obtained from the mentioned studies, from which it is clear that: a) high pressures favor the aromatization but also hydrogen transfer reactions. B) The presence of high amounts of Zn in the shaped catalysts also promotes dehydrogenation reactions –reducing the hydrogen transfer index. C) The results obtained in fixed bed do not change drastically when fluidizing the catalyst bed, meaning that the use of a fluidized bed reactor at larger scales is plausible for this process.

Figure 1. Yield of aromatics and hydrogen transfer indices after 4h on stream. Tests performed at 400 °C varying the pressure, kind of catalysts employed and flow regime.

Reference

I. Pinilla-Herrero, E. Borfecchia, J. Holzinger, U.V. Mentzel, F. Joensen, K.A. Lomachenko, S. Bordiga, C. Lamberti, G. Berlier, U. Olsbye, S. Svelle, J. Skibsted, P. Beato, Journal of Catalysis, 362 (2018) 146-163.

PK4

The use of UiO-type MOFs in gas phase Soai reactions

Giuseppe Rotunno, Gurpreet Kaur, Mohammed Amedjkouh, Karl Petter Lillerud, Unni Olsbye

Department of Chemistry, University of Oslo, Sem Sælands vei 26, 0371 Oslo
Email: Giuseppe.rotunno@smn.uio.no

In the last 20 years, the Soai reaction has drawn the attention of many research groups, as it is till date the only chemical reaction offering the chance to study the phenomenon of asymmetric autocatalysis in conjunction with high amplification of enantiomeric excess (ee) [1]. The chiral product of this reaction can catalyze its own production
enantioselectively, thus creating an asymmetric autocatalytic system coupled with amplification of the enantiomeric excess (ee %) of the product. The Catalysis group at the University of Oslo has gained a lot of experience since the discovery of the UiO-series of Zirconium Metal-Organic Frameworks [2] (MOFs), a relatively new and unexplored class of crystalline and porous materials involving strong metal-ligand interactions, whose application can be exploited in a wide range of areas, including catalysis. Here, we report a novel gas phase procedure to perform the Soai reaction: the substrate is confined in the pores of different UiO-type MOFs, and gas phase reaction with Zn(iPr)₂ are performed in a sealed environment, allowing the zinc vapours to react with the substrate. High enantiomeric excess
is obtained. Furthermore, different MOFs lead to different outcomes in terms of enantiomeric excess and handedness of the product. This is one of the first examples of Absolute Asymmetric Synthesis performed into a MOF.

Scheme of the Soai Reaction

References

Soai K., Shibata T., Morioka H., Choji K., Nature, 1995; 378, 767
Cavka, J.H., et al., J. Am. Chem. Soc., 2008. 130, 13850

PK5

A DFT study on the reaction mechanism of methane to methanol direct conversion via Cu-exchanged chabazite catalyst.

Carlo Buono¹, Pablo Beato2, Silvia Bordiga^1,3, Unni Olsbye¹ and Stian Svelle¹*.

Center for Materials Science and Nanotechnology (SMN), Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern N-0315 Oslo, Norway.
Haldor Topsøe A/S, Haldor Topsøes Alle ´ 1, 2800 Kongens Lyngby, Denmark.
Department of Chemistry, INSTM Reference Center and NIS Interdepartmental Centre, University of Turin, Via Quarello 15, I-10135, Turin, Italy.

* corresponding author: stian.svelle@kjemi.uio.no

The direct production of methanol from methane in a selective, direct, and low-energy process is a pursued goal by both industry and academy [1-3]. The importance of finding a low-energy process for the methane conversion is not only limited to production of methanol, a feedstock and liquid fuel with large applications in the chemical industry but it would have significant implications for the energy sector as well.

In this contribution, using Cu-exchanged zeolite, Cu-SSZ-13 (CHA topology) and low Al content, the formation of methanol from methane and water has been studied using dispersion corrected DFT-D3 [4] calculations in combination with ab initio molecular dynamics (AIMD). Four different active sites motifs, [CuOOCu]²⁺, [CuOCu]²⁺, [CuOO]⁺ and [CuOH]⁺ [1] have been considered for the methane activation. Different locations of the active site motifs were investigated to use the most stable configurations have for modelling the oxidation reaction.
The results demonstrate that methane can be oxidized but the activation process is the most difficult step. In addition, the most stable reaction intermediates have been found. Their detection by spectroscopic or other experimental techniques have important implications for the elucidation of the reaction mechanism. Finally, the difficulties of extracting methanol coordinating the metal center are discussed.

References

Dimitrios K. Pappas, Elisa Borfecchia, Michael Dyballa, Ilia A. Pankin, Kirill A. Lomachenko, Andrea Martini, Matteo Signorile, Shewangizaw Teketel, Bjørnar Arstad, Gloria Berlier, Carlo Lamberti, Silvia Bordiga, Unni Olsbye, Karl Petter Lillerud, Stian Svelle, and Pablo Beato, Journal of the American Chemical Society 2017 139 (42), 14961-14975 DOI: 10.1021/jacs.7b06472.
Vitaly L. Sushkevich, Dennis Palagin, Marco Ranocchiari, Jeroen A. van Bokhoven., Science 2017: Vol. 356, Issue 6337, pp. 523-527 DOI: 10.1126/science.aam9035.
Elisa Borfecchia, Pablo Beato, Stian Svelle, Unni Olsbye, Carlo Lamberti and Silvia Bordiga., Chem. Soc. Rev., 2018, Advance Article DOI: 10.1039/C8CS00373D.
Stefan Grimme, Jens Antony, Stephan Ehrlich and Helge Krieg, The Journal of Chemical Physics 132, 154104 (2010); DOI: 10.1063/1.3382344.

PK6

Bimetallic CuPt and CuPd nanoparticles prepared by Microwave Synthesis for CO₂ conversion to useful fuels

Maria Kalyva, Evgeniy Redekop, Giorgios Kalatzopoulos, Anette Eleonora Gunnæs , Spyros Diplas, Unni Olsbye

Nanocatalysts have emerged as a new class of materials, since they have been shown to exhibit superior properties for a range of catalytic processes compared to their bulk counterparts [1]. Nanomaterials prepared from earth-abundant and inexpensive metals, such as Copper (Cu), have attracted considerable attention because of their potential as viable alternatives to rare and expensive noble-metal catalysts used for reactions, such as, the carbon dioxide (CO₂ ) hydrogenation [2]. CO2 hydrogenation to valuable chemicals, such as alcohols, hydrocarbons and ethanol is considered a promising way for CO₂ mitigation and utilization with immense positive environmental impact [3].

Bimetallic Copper-Palladium (CuPd) nanoparticles (NPs), have been shown to be highly active catalysts for the CO₂ hydrogenation to ethanol due to their synergy, however, desirable conversion efficiency remains a challenge 4. Similarly, Copper- Platinum (CuPt) alloys have been shown to activate C–H bonds more efficiently than Cu and avoid the problem of coking typically encountered with Pt [5]. To investigate further this reaction, we have prepared CuPd and CuPt NPs nanocatalysts using microwave synthesis. Microwave heating is considered to be a ‘greener’ nanosynthesis method, since, it requires shorter reaction times, reduced energy consumption, and has higher yields compared to the other wet chemical methods [6]. The prepared NPs have been characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy
(XPS). After deposition of the NPs onto Al₂O₃ support, their catalytic activity and selectivity towards CO₂hydrogenation was tested. The powders were characterized pre-and post reaction by XPS and TEM. Our goal is the direct correlation of the NPs’ surface chemistry and structure of each noble metal with the acquired properties, in order to elucidate the mechanism and control this sustainable reaction.

References

S. B. Singh, P. K. Tandon, Journal of Energy and Chemical Engineering , 2014, Vol. 2 Iss. 3, PP. 106-115
F. Zaera, Chem. Soc. Rev. 2013, 42,2746– 2762
M. He, Y. Sun, B. Han, Angew. Chem. Int. Ed. 2013, 52,9620–9633
S. Bai, Q. Shao, P. Wang, Q. Dai, X. Wang and X. Huang, J. Am. Chem. Soc., 2017, 139 (20), pp 6827–6830
M. D. Marcinkowski , M. T. Darby , J. Liu, J. M. Wimble, F. R. Lucci, S. Lee, A. Michaelides, M. Flytzani-Stephanopoulos, M. Stamatakis & E. C. H. Sykes, Nature Chemistry , 2018, 10, pp. 325–332
J. A. Dahl, B. L. S. Maddux, J. E. Hutchison, Chem. Rev. 2007, 107, 2228

PK7

Real-time regeneration of a working zeolite monitored via operando space-resolved X-Ray diffraction

Georgios N. Kalantzopoulos*, Daniel Rojo Gama, Dimitrios K. Pappas, Karl Petter Lillerud, Unni Olsbye, David S. Wragg and Stian Svelle.

Department of Chemistry, University of Oslo, Sem Sælands vei 26, N-0371 Oslo, Norway.
*georgiok@smn.uio.no.

H-ZSM-5 is known to be the archetype zeolite for the conversion of methanol to gasoline (MTG) due to its
three dimensional structure consisting of straight and sinusoidal channels that enhance the diffusion of
products, improving the resistance towards deactivation. One of the main hurdles that a zeolite framework
inherently exhibits when used as a catalyst in the MTG reaction is the loss of catalytic performance over time.
The loss of activity on H-ZSM-5 during the MTG reaction is reported to follow the “burning cigar” model
proposed by Haw[1,2,3]. Exposure of the catalyst to suitable oxidative conditions leads to the burning of the
coke, making the acid sites accessible for a consecutive MTG cycle. To the best of our knowledge, very little
is reported regarding the evolution of the H-ZSM-5 structure during its regeneration. In this work we have
used operando space-resolved X-Ray diffraction to study the local structural transformations of the HZSM-
5 catalyst during the removal of coke under variable temperature oxidative conditions, resulting in
catalyst regeneration.

Figure 1. Evolution of individual coke occupancies within the ZSM-5 framework during regeneration at increasing time on stream (TOS).

References

Catal. Today. 2010, 154, 183-194.
Rojo-Gama, D.; Etemadi, S.; Kirby, E. et al, Faraday Discuss. 2017, 197, 421-446.
Haw, J. F.; Marcus, D. M. Top Catal 2005, 34, 41-48.

PK8

Ethene dimerization with metal-organic framework (MOF) functionalized with Ni(II) and bipyridine

Mustafa Kømurcu¹, Andrea Lazzarini¹, Gurpreet Kaur¹, Silvia Bordiga², Unni Olsbye^1*

1 – Department of Chemistry, University of Oslo, P.O. Box 1033, Oslo 0315, Norway
2 – Univerisity of Turin, Department of Chemistry, Via P. Giuria 7, Turin 10125, Italy
* corresponding author Unni.olsbye@kjemi.uio.no

Ethene dimerization is a straightforward solution to produce the more in demand and valuable linear and branched butenes. Dimerization of ethene to linear α-butene is one of the few large-scale homogeneously catalyzed reactions [1]. With the intention of making the process more practical and sustainable, research attention has been focused on the development of heterogeneous processes. Ni-aluminosilicates have for a long time been the most promising catalyst, but now metal-organic framework (MOF) based selective oligomerization catalysts are appearing [2, 3]. The upside of Ni-aluminosilicate catalysts is that do not require a co-catalyst (Et₂AlCl), unlike homogeneous and MOF-based catalyst. In here, we report the first MOF-based catalyst that show significant dimerization activity without the use of a co-catalyst.

UiO-67, UiO-67-bpy_7% and UiO-67-bpy_12% (bpy = 2,2’bipyridine-5,5’-dicarboxylate) have been functionalized with Ni²⁺ and characterized by XRD, SEM, N2-adsorption and FT-IR. The samples were tested as ethene dimerization catalysts at T = 250 °C, P(total) = 30 bar where P(ethene) = 26 bar. High temperatures (> 200 °C) and ethene partial pressure (> 4 bar) was necessary for significant conversion. Only catalysts with high concentration of Ni and bpy showed significant activity where the main products were linear butenes. An initial increase in ethene conversion with time on stream was observed, suggesting that the active site is formed during reaction. The catalysts deactivated over the course of the experiments due to long chain alkenes retained in the structure. Catalytic activity increased with activation time, where longer duration at elevated temperature led to a higher conversion and faster achievement of maximum conversion. TEM images and FTIR measurements show the presence of Ni/O nanoparticles on spent catalyst. Ex-situ CO-FTIR measurements on catalyst used for 0, 100 and 700 min TOS show that Ni nanoparticles form only after several hours TOS, eliminating the possibility of Ni/O nanoparticles as the single active site for the reaction. Ni2+ grafted on bpy linkers is suggested as the active site for this reaction. Switching the feed from ethene to 1-butene, no isomerization or dimerization was observed over the bpy-UiO-67. Considering the lack of strong acid sites and taking the product distribution to account the Ni-UiO-67-bpy catalyst is suggested to operate through the Cossee-Arlman mechanism.

References

McGuinness, D.S., Olefin Oligomerization via Metallacycles: Dimerization, Trimerization, Tetramerization, and Beyond. Chemical Reviews, 2010. 111(3): p. 2321-2341.
Hulea, V., Toward Platform Chemicals from Bio-Based Ethylene: Heterogeneous Catalysts and Processes. ACS Catalysis, 2018. 8(4): p. 3263-3279.
Finiels, A., F. Fajula, and V. Hulea, Nickel-based solid catalysts for ethylene oligomerization - a review. Catalysis Science & Technology, 2014. 4(8): p. 2412-2426.

PK9

Synthesis and characterization of gold(I) NHC complexes suitable as FEBID precursors

Cristiano Glessi^1*, Jakub Jurczyk^2,3, Ivo Utke² and Mats Tilset¹

Department of Chemistry, University of Oslo, N-0315, Oslo, Norway
EMPA, Swiss Federal Laboratories for Material Science and Technology, 3602 Thun, Switzerland
Faculty of Physics and Applied Computer Sciences, AGH University of Science and Technology Krakow, 30-059 Krakow, Poland

* cristiano.glessi@smn.uio.no

The development of compounds specifically designed to be applied as FEBID precursors is of pivotal importance in the progress of this field. Due to its properties gold has so far proven to be of main interest in the FEBID community.
In this contribution we report on several organometallic gold(I) complexes bearing an NHC (N-heterocyclic carbene) ligand that are suitable as FEBID precursors. These compounds differ for the nature of the substituents on the nitrogens on the NHC, for the backbone substitution and for the nature of the other ligand present on the gold(I) center. A full array of compounds have been synthesized, characterized and studied aiming for a better understanding of the effect of the various substitutions both on the solid state properties of the compounds and on their thermogravimetric and physical properties.

As one of the key properties of the precursors is that they have to be stable in gas phase and volatile at moderate temperatures, the application of well established procedures together with the development of new thermogravimetric characterization tools is of focal importance. A link between the complexes structure and their sublimation temperature will be discussed via a series of different chemical and physical characterization techniques such as NMR spectrometry, X-ray crystallography, Thermogravimetric analysis and sublimation methods. A thermogravimetric analysis tool (vacuum-TGA) has been developed for the study of low-volatility organometallic complexes (Figure 1) and the preliminary results will be presented.[1]

Figure 1: Vacuum TGA of three selected gold complexes and square deposit made with IEtAuCl.

References

G. V. Kunte, S. A. Shivashankar, A. M. Umarji, Meas. Sci. Technol. 19 (2008), 025704.

PK10

Production of high surface area zirconium oxides through thermal metamorphosis of metal organic frameworks.

Christopher W. Affolter, Evgeniy A. Redekop*, Sigurd Øien-Ødegaard, Maria E. Kalyva, Emil S. Gutterød, Karl-Petter Lillerud, and Unni Olsbye

Centre for Materials Science and Nanotechnology (SMN), Department of Chemistry, University of Oslo, Norway
* corresponding evgeniyr@smn.uio.no

High surface area zirconium oxides are important for technologically-relevant materials that are often used as catalyst supports and as components of electrochemical devices. Conventional preparations of such materials rely on methods such as precipitation from salt solutions that rarely afford significant surface areas. Active catalytic ingredients such as transition metals are either co-precipitated with zirconia and later reduced or deposited onto zirconia in post-synthetic steps. These synthesis protocols offer limited control over the properties of catalytic interfaces between zirconia and metal nanoparticles that are essential for the catalytic function, e.g. in the prototypical Cu/ZrO₂ system for methanol synthesis from CO₂. We have developed another approach to produce high surface area zirconia and its derivatives through controlled thermal treatment of Zr-based Metal-Organic Frameworks (MOFs) [1,2]. This metamorphosis procedure results in a high-surface area (>100 m2/g) materials that largely retain the morphological features of the parent MOF (see Figure 1). We have applied a range of metal deposition techniques including wet impregnation with salt solutions and Chemical Vapor Impregnation (CVI) in vacuum to construct Cu/ZrO₂ interfaces before as well as after MOF decomposition. The process of MOF decomposition and the physico-chemical properties of the resulting materials were characterization using a range of techniques (XRD, SEM, TGA, TPD, XPS, TEM, TAP, etc.). Herein, we discuss these results with the emphasis on potential applications in catalyst design and on the remediation of the scale-up issues we have encountered with metal deposition into MOFs as well as MOF decomposition process.

Figure 1. MOF-derived zirconia with preserved morphology of the parent MOF crystallites.

References

Cavka et al., J. Am. Chem. Soc. 130 (2008) 13850–13851.
A. Indra et al., Adv. Mater. (2018) 1705146

PK11

Magnetic properties of [NpO₂(dpc)₂]^2- in solid and in solution

Julie Héron¹, Hélène Bolvin^2*

1. Hylleraas Centre for Quantum Molecular Sciences, Universitetet I Oslo, Norway
2. Laboratoire de Chimie et de Physique Quantiques, Université Toulouse 3, France
* corresponding bolvin@irsamc.ups-tlse.fr

Magnetic properties of the [NpO2(dpc)2]2- have been characterised both in solid and in solution. In solid state, the experiments have been performed in the teem of E. Colineau using SQUID (UIT in Karlsuhe) and in solution by the team of C. Berthon (CEA Marcoule) using the p-NMR and the Evans method. The susceptibility differ by 20% between the two states.

The calculation of properties of open shell 5f molecules os a challenge for the methods of quantum chemistry: these complexes have many low- lying configurations, spin-orbit effects anre important and correlation effects must be taken into account. The SO-CASPT2 method gives results that compare well to experimental data: it is a two step wave function based method. The multiconfigurational nature of the wave function is described by starting a CASSCF calculation, correlation effects are calculated by second order theory and spin-orbit effects are introduced in the very last step by an interaction procedure.

NpO₂²⁺ is in the 5f¹ configuration and it has been already shown that the equatorial ligands play an important role for the determination of the nature of the ground state [1]. We performed quantum chemical calculation with SO-CASPT2 in order to analyze these differences. For the present complex, our calculation are in good agreement with the experimental data nd we show that the Li⁺ countet ion present in the solid star play a jey role.

Example reference

F. Gendron, D. Paez Hernandez, F. P. Notter, B. Pritchard, H. Bolvin, J. Autschbach Chem. Eur. J. 2014, 20, 7994.

PK12

Biomimetic copper complexes for incorporation into MOFs

Isabelle Gerz, Unni Olsbye, Mats Tilset, Mohamed Amedjkouh

Department of Chemistry – University of Oslo, Norway

Lytic polysaccharide monooxygenases (LPMOs) cleave polysaccharides oxidatively.[1] Their application in industrial processes and their ability to selectively oxidise a substrate make it of interest to create biomimetic complexes. Such a complex could for one further the understanding of the enzyme but also be a relevant catalyst on itself.[2,3]

A histidine brace surrounding a copper ion has been singled out in literature as an essential structural motive for the enzymes reactivity.[4] This provided inspiration for the design of a variety of copper complexes with coordinating N-heterocycles with suitable ligand backbones for incorporation into UiO-67 Metal Organic Frameworks (MOFs). The encapsulated Cu-complex is aimed for heterogenous catalysis for the C-H activation in the selective oxidation of light alkanes.

References

T. J. Simmons, K. E. H. Frandsen, L. Ciano, T. Tryfona, N. Lenfant, J. C. Poulsen, L. F. L. Wilson, T.Tandrup, M. Tovborg, K. Schnorr, et al., Nat. Commun. 2017, 8, 1064.
V. C.-C. Wang, S. Maji, P. P.-Y. Chen, H. K. Lee, S. S.-F. Yu, S. I. Chan, Chem. Rev. 2017, 117, 8574–8621.
A. L. Concia, M. R. Beccia, M. Orio, F. T. Ferre, M. Scarpellini, F. Biaso, B. Guigliarelli, M. Réglier, A. J. Simaan, Inorg. Chem. 2017, 56, 1023–1026.
K. S. Johansen, Biochem. Soc. Trans. 2016, 44, 143–149.

PK13

A Niobia-Supported Iridium-Based Catalyst for Deoxygenation of Lignin-Derived Model Compounds

Simen P. Følkner, Raju Dey, Giovanni Occhipinti, Vidar R. Jensen, Erwan Le Roux

University of Bergen

Lignin is a very abundant biomass and an excellent source of renewable aromatic hydrocarbons and cycloalkanes, which are desired components in biofuels. Still, efficient and sustainable routes from the polymeric, highly functionalized lignin to the depolymerized, reduced hydrocarbons have yet to be established. Through processes such as the solvolytic lignin-to-liquid process (LtL), a uniform and tunable bio-oil, consisting of different phenolic compounds can be obtained. Using such depolymerized model compounds, the deoxygenation alone is the focus of catalytic upgrading toward biofuels. Promising results for hydrodeoxygenation by molecular iridium hydride catalysts inspired us to develop a novel niobia-supported catalyst based on iridium trichloride (IrCl₃) for the selective and quantitative conversion of model compounds derived from LtL bio-oils into cycloalkanes.

PM - Makromolekyl- og kolloidkjemi

PM1	Liposomes as a model system for the study of surface active peptides. V.A. Bjørnestad (UiO)
PM2	Interactions between Anionic Surfactants and Polymeric Micelles: stability and solubilisation kinetics. Synne Myhre (UiO)
PM3	Thin film breakage in the interphase region formed between two interacting drops. Enrico Riccardi (NTNU)

Abstracts

PM1

Liposomes as a model system for the study of surface active peptides

V.A. Bjørnestad, J.E. Nielsen and R. Lund

Department of Chemistry, University of Oslo

The lipid-specific interactions of antimicrobial peptides (AMPs) are well established but have not been properly characterised [1]. Liposomes, i.e. vesicles of phospholipid bilayers, mimicking bacterial and mammalian membranes can be used as model systems for investigating these changes. Using small angle X-ray (SAXS) techniques, structural changes that occur in the bilayer can be monitored in real time in solution.

Liposomes mimicking bacterial membranes precipitate in the presence of cationic AMPs due to the negative charge of the bilayer. The liposomes were sterically stabilised against aggregation by either adding end-modified n-alkane-poly(ethylene oxide) (Cn-PEO) or by incorporating poly(ethylene oxide)-modified phospholipids (""PEGylated"" lipids) into the bilayer. While addition of Cn-PEO polymers stabilised towards aggregation, the polymers had competing interactions with the peptides and modified the lipid bilayer [2]. The PEGylation successfully stabilised the liposomes without modifying the bilayer or preventing their interaction with AMPs. To obtain quantitative data about the structural changes using SAXS, analytical scattering models describing the detailed liposomal structure and the intercalation of peptide into the membrane were developed. These were able to fully account for the experimental data. The AMP Indolicidin was found to intercalate into the hydrocarbon region of the liposomal bilayer, destabilising the membrane by disrupting the packing of the lipids [3]. The Indolicidin also caused growth of the vesicles, suggesting that the destabilisation causes increased lipid exchange between the liposomes. The developed methods and analytical models provide an efficient structural method for probing lipid-peptide interactions that may also elucidate the mechanism of other types of AMPs.

References

R.E.W. Hancock and A. Rozek, FEMS Microbiology Letters 2002, 206, 143-149.
V.A. Bjørnestad, J.E. Nielsen, and R. Lund, Manuscript in preparation 2018.
J.E. Nielsen, V.A. Bjørnestad, and R. Lund, Unpublished manuscript 2018.

PM2

Interactions between Anionic Surfactants and Polymeric Micelles: stability and solubilisation kinetics

Synne Myhre(a), Matthias Amann(a), Lutz Willner(b), Kenneth D. Knudsen(c) and Reidar Lund(a)

(a) Department of Chemistry, Sem Sælandsvei 26, 0314 Oslo, Norway
(b) Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52428 Jülich, Germany
(c) IFE, Institute for Energy Technology, Instituttveien 18, 2007 Kjeller, Norway"

The kinetic processes involved in mixtures of surfactants and block copolymer micelles are not well understood. However, it is commonly known that surfactants exhibit rather fast equilibration kinetics, in the order of micro- to milliseconds, while polymers are much slower, in the order of minutes to months. In this contribution, we will present a study of the stability and solubilization kinetics of block copolymers micelles upon addition of sodium dodecyl sulphate (SDS) using small angle X-ray scattering (SAXS) and time resolved neutron scattering (TR- SANS). We compare the ability of the surfactant to dissolve and form mixed micelles with two amphiphilic polymers; poly(ethylene propylene)-poly(ethylene oxide) (PEP-PEO) and end- capped PEO (C28-PEO). While the kinetics of C28PEO occurs on time scales on the order of minutes-hours on ambient temperatures, that of PEP1-PEO20 is known to be frozen on practical time scales. Addition of SDS to PEP1-PEO20 shows close to no change, even after extended period of time. However, upon addition of SDS to C28PEO5 we observe a fast dissolution and formation of mixed micelles, where the kinetics is seen to accelerate with the amount of added surfactant.

PM3

Thin film breakage in the interphase region formed between two interacting drops.

Enrico Riccardi

NTNU

Surfactants adsorbed on droplets alter the surrounding interphase region. During coalescence, drops interact via the overlapping interphases, forming a thin film layer. The intermolecular interactions dictate its properties and stability. We aim to describe, at atomistic scale, the process involved in the thin film breakage via advanced molecular dynamics simulation (i.e. rare events method). We intend to discriminate the mechanisms and quantify their rate in the thin film breakage as a function of physical (P and T) and chemical (surfactants, ion type, solid particles, asphaltenes) variables.

interacting droplets. We aim to capture the mechanism responsible for the
coalescence models.

PU - Uorganisk kjemi og materialkjemi

PU1	In situ prepared epoxy nanocomposites for high voltage insulation Mohammed Mostafa Adnan (NTNU)
PU2	Investigation of characterization methods for new porous functional materials Daniel Ali (NTNU)
PU3	Double perovskite oxides as electrocatalysts for the oxygen evolution reaction H. Andersen (UiO)
PU4	Pyrolysis of silanes and silane mixtures – kinetic modelling and experiments using a benchtop reactor S.G. Anjitha (?)
PU5	Formation and characterisation of a Cu2O – ZnO p–n–Junction K. G. Both (UiO)
PU6	Amorphous FePO4 in thin film batteries Anders Brennhagen (UiO)
PU7	Black titania nanotubes with tunable crystal orientation for supercapacitors A. Chatzitakis (UiO)
PU8	The effect of crystallite size and donor doping on the conductivity and oxygen absorption of hexagonal RMnO_3+δ Frida Paulsen Danmo (NTNU)
PU9	Key challenges in fabrication of metal-supported proton conducting electrolyser cells Amir Masoud Dayaghi (UiO)
PU10	Influence of ionic species and metal oxide - carbonate phase transformations on the ionic conduction behaviour of Gd-doped ceria - Li₂CO₃/Na₂CO₃ composite membranes V. S. Dilimon (UiO)
PU11	Novel Molten/solid Composite Oxygen Transport Membranes for CO₂ Capture Linn Katinka Emhjellen (UiO)
PU12	Point Defects in Monolayer MoS₂ Christian Fleischer
PU13	DFT study of a stable junction between p-type NiO and n-type ZnO Emil Frøen (UiO)
PU14	Search for functional materials demonstrating Giant Magnetostructural Phase transition for Solid State Refrigeration applications Nicolai Hauffen (UiO)
PU15	Ionic, protonic and electronic conductivity in Li₇La₃Zr₂O_12-based materials J. Kolding (UiO)
PU16	Phosphites as precursors in thin film synthesis. Using LiPO₄ as cathode coating in Li-ion batteries. Kristian B. Kvamme (UiO)
PU17	Enzyme-assisted Catalysis on Black Titania Electrodes X. Liu (UiO)
PU18	Preparation and characterization of Ru/CeO2 catalysts for electrically enhanced ammonia synthesis Quanbao Ma (UiO)
PU19	Self-assembled Ni_0.98Li_0.02O and Zn_0.98Al_0.02O composite interface for thermoelectrics Reshma Krishnan Madathil (UiO)
PU20	Mechanistic study by impedance spectroscopy of the positrode reaction on proton ceramic electrochemical cells Madeeha Khalid Pedersen (UiO)
PU21	Operando XRD-CT investigation of a BiVO4 anode Amund Ruud (UiO)
PU22	Verification of hierarchical porosity in CuSAPO-34 by in situ XAS, N2 adsorption measurements and NO_x removal Guro Sørli (NTNU)
PU23	Solid-state tandem photoelectrochemical cell for wet air electrolysis and hydrogen production K. Xu (UiO)
PU24	Pt_100-xRh_x/Al₂O₃ catalysts for ammonia oxidation at intermediate temperatures. P. Dhak (UiO)
PU25	Conductivity of polymer-ceramic composite membranes at high T and p(H₂O) using a novel PEEK sample holder. A. Chatzitakis (UiO)
PU26	DFT study on proton uptake in BaFeO_3-x Maximilian Felix Hoedl

Abstracts

PU1

In situ prepared epoxy nanocomposites for high voltage insulation

Mohammed Mostafa Adnan

Department of Materials Science and Engineering, NTNU

Epoxy-based nanocomposites, containing inorganic oxide nanoparticles as filler, display novel properties making them suitable for application in nanodielectrics, such as in microelectromechanical systems and high voltage insulation [1,2]. Due to the difficulty in achieving homogenous dispersion of non-agglomerated nanoparticles in the epoxy via conventional fabrication methods, there are, however, challenges in obtaining the desired dielectric properties [3]. The use of sol-gel to synthesize the nanoparticles in situ in the epoxy is an attractive alternative route for fabrication [4,5]. We show that for small concentrations of SiO2 (below 5 wt%) synthesized in situ, the complex permittivity of epoxy-SiO2 hybrids is decreased from that of pure epoxy, and the thermal stability and glass transition temperature is increased, thereby improving their performance as materials for high voltage insulation. The dielectric breakdown strength of these nanocomposites will also be investigated.

References:

Tanaka, T. Dielectric Nanocomposites with Insulating Properties. IEEE Trans. Dielectr. Electr. Insul. 2005, 12, 914–928.
Singha, S.; Thomas, M. J. Dielectric properties of epoxy nanocomposites. IEEE Trans. Dielectr. Electr. Insul. 2008, 15, 12–23.
Calebrese, C.; Hui, L.; Schadler, L. S.; Nelson, J. K. A Review on the Importance of Nanocomposite Processing to Enhance Electrical Insulation. IEEE Trans. Dielectr. Electr. Insul. 2011, 18, 938–945.
Matějka, L.; Pleštil, J.; Dušek, K. Structure evolution in epoxy–silica hybrids: sol–gel process. J. Non. Cryst. Solids 1998, 226, 114–121, doi:10.1016/S0022-3093(98)00356-1.
Matějka, L.; Dušek, K.; Pleštil, J.; Kříž, J.; Lednický, F. Formation and structure of the epoxy-silica hybrids. Polymer (Guildf). 1999, 40, 171–181, doi:10.1016/S0032-3861(98)00214-6.

PU2

Investigation of characterization methods for new porous functional materials

Daniel Ali, Hilde Lea Lein†, Karina Mathisen,

*Department of Chemistry, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim, Norway. †Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim, Norway.

Corresponding author, email: daniel.ali@ntnu.no

Molecular diffusion in intracrystalline pores is inherently slow, and consequently only the outer regions of the zeotype catalyst particles will partake in the conversion. To ameliorate this, a recent focus has been directed at the synthesis of materials possessing a bimodal porosity distribution, so-called hierarchical materials, where meso pores are thought to increase catalytic properties and reduce accumulation of coke by functioning as super highways for reactants and products to enter and exit the structure1,2. Multiple materials have been prepared with such properties, among which are the silicoaluminophosphates (SAPOs) SAPO – 5 and SAPO – 342,3.
The critical issue for these materials lies in the fundamental characterization of the pore characteristics to ensure that the meso- and micro pores are connected and accessible to reactants from the external surface. Thus, the goal of this project is to investigate and elucidate new and current methods for characterization of porosity.
FT-IR with probe molecules, TPD and BET are techniques well suited for determining pore characteristics and may help to determine if meso- and micro pores are interconnected4,5. Another approach is to utilize shape selective model reactions or reactions where buildup of coke can be detrimental to activity. One example of the latter is the methanol to olefin reaction (MTO), a process where the small pore SAPO-34 is already a well-established catalyst, albeit with a limited lifetime namely due to coking. Increased lifetime of SAPO-34 for MTO reaction by introducing mesopores has already been reported6,7. Other reactions typically employed for probing shape selectivity include oligomerization or hydroxylation reactions8.

References:

Kustova, M. Y.; Rasmussen, S. B.; Kustov, A. L.; Christensen, C. H. Applied Catalysis B: Environmental 2006, 67, 60.
Yang, H.; Liu, Z.; Gao, H.; Xie, Z. Journal of Materials Chemistry 2010, 20, 3227
Danilina, N.; F. Krumeich, and J.A. van Bokhoven, Journal of Catalysis, 2010. 272, 37
Reichinger, M.; Schmidt, W.; Berg, M. W. E. v. d.; Aerts, A.; Martens, J. A.; Kirschhock, C. E. A.; Gies, H.; Grünert, W. Journal of Catalysis 2010, 269, 367.
5. Sun, Q.; Wang, N.; Guo, G.; Chen, X.; Yu, J. Journal of Materials Chemistry A 2015, 3, 19783.
Milina, M.; Mitchell, S.; Crivelli, P.; Cooke, D.; Pérez-Ramírez, J. Nature Communications 2014, 5, 3922.
Kim, J.; Choi, M.; Ryoo, R. Journal of Catalysis 2010, 269, 219.
Yang, G.; Wei, Y.; Xu, S.; Chen, J.; Li, J.; Liu, Z.; Yu, J.; Xu, R. The Journal of Physical Chemistry C 2013, 117, 8214.

PU3

Double perovskite oxides as electrocatalysts for the oxygen evolution reaction

H. Andersen, A. Chatzitakis, R. Strandbakke,* T. Norby

Department of Chemistry, University of Oslo, SMN, FERMiO, Gaustadalléen 21, NO-0349 Oslo, Norway
Tel.: +47 22840660

ragnar.strandbakke@kjemi.uio.no

Double perovskite oxides BaPrCo_1,4Fe_0,6O_6-δ (BPCF), BaGbCo₁,8Fe_0,2O_6-δ (BGCF) and BaPrCo₂O_6-δ(BPC) were tested as anode electrodes for the oxygen evolution reaction (OER) in alkaline environment. The electrocatalytic activity for the OER in 1 M NaOH was studied by using a rotating disk electrode (RDE) and all materials were compared against the state-of-the-art IrO2. The results indicate that BGCF is the best electrocatalyst among the three perovskite oxides with a Tafel slope of 55,7 mV dec-1, which is close to the 32,6 mV dec-1 of IrO2. The onset overpotential for the OER (taken at 1 mA cm-2) for BGCF was 375 mV and 250 mV for IrO2, while the overpotential at a current density of 10 mA cm-2 was 460 mV and 300 mV, respectively. Moreover, the stability of GBCF was tested by depositing approx. 1 mg cm-2 of BGCF on a Ni foam substrate. A galvanostatic run at 10 mA cm-2 showed that the overpotential was reduced from 366 mV to 348 mV after 4 h of operation, implying the excellent stability of the material under strong alkaline conditions. This work demonstrates that perovskite oxides based on non-precious elements have the potential to replace the gold standards of OER such as IrO2 and RuO2 [1].

Figure 1: Linear sweep voltammograms of BaPrCo_1,4Fe_0,6O_6-δ, BaGbCo_1,8Fe_0,2O_6-δ, BaPrCo₂O_6-δ and IrO₂ on glassy carbon electrode in 1 M NaOH, at 10 mV s-1 scan rate, at 1000 rpm. The dashed lines show the IR corrected curves.

Reference:

J. Suntivich et al., Science, 334 (2011) 1383.

Acknowledgement: This work was performed within MoZEES, a Norwegian Centre for Environment-friendly Energy Research (FME), co-sponsored by the Research Council of Norway (project number 257653) and 40 partners from research, industry and public sector. We also acknowledge funding from the Research Council of Norway (Grant nᵒ 272797 “GoPHy MiCO”) through the M-ERA.NET Joint Call 2016.

PU4

Pyrolysis of silanes and silane mixtures – kinetic modelling and experiments using a benchtop reactor

Anjitha S G, T. J. Preston, G. Marie Wyller.

Institute for Energy Technology - Kjeller (Norway)

Silane pyrolysis is an important reaction in production of silicon and silicon containing compounds. Silicon is widely used in solar cells and in semiconductor industry. Another application of these materials is in batteries. For example, silicon nitride is used as anode material in Li ion batteries. Studying the reactions in silicon pyrolysis is useful in understanding the production process of silicon, silicon nitride or similar materials.

Pyrolysis of silanes progress through a series of higher order silanes before particle production. The structure and size of these higher order silanes can change with temperature, pressure and other reaction conditions. The characteristics of the higher order silanes influences the particle produced. When silicon nitride is used as an anode material of batteries, the silicon content, size, shape, roughness of particle, etc. influence its electrical properties. Modelling the kinetic scheme of silane pyrolysis is one way to understand the production of higher order silanes. Theoretical studies focusing on the Si particle formation and Si nucleation are numerous. This study is focusing on the reactions in gaseous phase. A group additivity scheme proposed by Adamczyk et al.1 is used to calculate the Arrhenius rate parameters Ea (activation energy) and A (pre-exponential factor). A kinetic scheme to understand the process is developed using these parameters. Silane pyrolysis experiments are done in parallel to validate the kinetic scheme. The reactions are done in a simple bench-top free space reactor and the products are analysed in GC-MS2. Previously reported experimental studies in silane pyrolysis are few. The lack of experimental data leads us to calculating some physical parameters. With the main goal of aiding experiments, retention indexes are related to boiling point.

References:

Adamczyk et al., ChemPhysChem 9000, 1978–1994. (2010). https://doi.org/10.1002/cphc.200900836
Wyller et al., J Crystal Growth. Accepted manuscript (2018). https://doi.org/10.1016/j.jcrysgro.2018.03.024
Wiener, H., J. Am. Chem. Soc. 69, 1, 17-20. (1947) https://doi.org/10.1021/ja01193a005

PU5

Formation and characterisation of a Cu2O – ZnO p–n–Junction

K. G. Both, C. Bazioti, T. S. Bjørheim, O. M. Løvvik, T. Norby

Centre for Materials Science and Nanotechnology (SMN), University of Oslo, POB 1126 Blindern, NO-0318 Oslo, Norway

Since the first patent describing a functional p-n-junction in the 1940s by Russel Ohl [1], the technology has developed into today’s diodes, LEDs, solar cells, transistors, and integrated circuits. While the working principle remains the same, the dimensions have decreased manifold. This creates challenging requirements for the materials used. Additionally, increasing the junction’s lifetime and robustness would further extend the specifications of these materials.

The two sides of the p-n-junction are an acceptor-doped sector (p-doped), containing mobile electron holes in the valence band, and a donor-doped one (n-doped), containing mobile electrons in the conduction band. Current can be conducted well in either one of the domains if no domain boundary is crossed. If such an interface is created and crossed by a current, the material will behave in different ways, depending on the direction of the current, and the applied bias. A depletion zone is formed around the interface, leading to two distinct behaviors, depending on the current’s direction. For a negative voltage and desired current from the n-doped to the p-doped material (negative current), the results are poor. The p-n-junction effectively minimizes the negative current. Additionally, if a positive voltage is applied and a current is flowing from the p-doped domain to the n-doped (positive current), more voltage must be applied to create a current than typically has to be in a purely n-doped material. Hence, the junction is rectifying, a property used in electronics. The higher resistance is an undesirable property, as it heats up the device. However, with increasing voltage, the resistance can be reduced to the order of the resistance of a single domain material.

A p-n-junction can be designed in two different ways. Most junctions have two differently doped domains of the same material hence with the same band-gap. The second approach is to use two different materials hence a heterojunction with different bandgaps, dopants, and/or p- and n-type conduction. A heterojunction introduces a grain boundary between the two domains, which may introduce lattice mismatches, altering the mobility of the two charge carriers. Despite this new challenge, the second approach has benefits, too. The use of materials that are neighbors in a phase diagram prevents the two domains to interdiffuse, and consequently from obliterating the junction.

Cuprite (Cu2O) and zinc oxide (ZnO) form such a couple, and the manufacture of a coexistent p-n-junction with the two has gotten some attention due to its potential as cheap, non-toxic top-layer for solar cells [2-4]. Nonetheless, a reliable method to create a clean and atomically sharp interface has not yet been discovered [5, 6]. The main inconvenience is a five-nanometer thick tenorite (CuO) layer forming at the interface. This layer forms due to the presence of a source of oxygen (e.g. omnipresent O2 or H2O gas species) and additional driving force from strain and lowering of interface energies. To understand and possibly avoid the formation of the tenorite layer, the crystal structure of the two copper oxides, zinc oxide, and the interfaces is essential. This poster aims to state a possible explanation why a tenorite layer is formed, based on DFT calculations, to determine the composition of the cuprite and zinc oxide domains, both experimentally, and suggest an approach, using pulsed laser deposition, how to force the system to avert a tenorite layer altogether.

References:

R.S. Ohl, Light-sensitive electric device including silicon, Google Patents, 1948.
Y. Ievskaya, R.L.Z. Hoye, A. Sadhanala, K.P. Musselman, J.L. MacManus-Driscoll, Fabrication of ZnO/Cu2O heterojunctions in atmospheric conditions: Improved interface quality and solar cell performance, Sol Energ Mat Sol C 135(Supplement C) (2015) 43-48.
T. Minami, Y. Nishi, T. Miyata, J. Nomoto, High-Efficiency Oxide Solar Cells with ZnO/Cu2O Heterojunction Fabricated on Thermally Oxidized Cu2O Sheets, Appl Phys Express 4 (6) (2011).
T. Minami, Y. Nishi, T. Miyata, Cu2O-based solar cells using oxide semiconductors, J Semicond 37 (1) (2016).
J. Gan, S. Gorantla, H.N. Riise, Ø.S. Fjellvåg, S. Diplas, O.M. Løvvik, B.G. Svensson, E.V. Monakhov, A.E. Gunnæs, Structural properties of Cu2O epitaxial films grown on c-axis single crystal ZnO by magnetron sputtering, Applied Physics Letters 108 (15) (2016) 152110.
A.E. Gunnæs, S. Gorantla, O.M. Løvvik, J. Gan, P.A. Carvalho, B.G. Svensson, E.V. Monakhov, K. Bergum, I.T. Jensen, S. Diplas, Epitaxial Strain-Induced Growth of CuO at Cu2O/ZnO Interfaces, The Journal of Physical Chemistry C 120 (41) (2016) 23552-23558.

PU6

Amorphous FePO4 in thin film batteries

Anders Brennhagen, Ola Nilsen

Department of Chemistry, University of Oslo

Thin film amorphous FePO₄ prepared by ALD is showing some interesting properties as a cathode material. It has very good cycling stability and can handle a reversible charging rate of 2560 C, which corresponds to 1,5 s.

PU7

Black titania nanotubes with tunable crystal orientation for supercapacitors

A. Chatzitakis,¹* X. Liu,¹ P. A. Carvalho,² M. Norderhaug Getz,¹ T. Norby¹

1 Department of Chemistry, University of Oslo, SMN, FERMiO, Gaustadalléen 21, NO-0349 Oslo, Norway
2 SINTEF Industry, P.O. Box 124 Blindern, NO-0314 Oslo, Norway

Tel.: +47-22840693
a.e.chatzitakis@smn.uio.no

Supercapacitors bridge the energy and power gap between the traditional dielectric capacitors, batteries and fuel cells. The ideal electrode material for supercapacitors must have high electronic conductivity, high surface area and good wettability. Hydrogenated TiO2, known also as black titania, in the form of nanotubes (TNTs) has the potential to meet all these requirements. Here, we present a simple, one-step hydrogenation procedure in the presence of CaH2, which allows us to fine-tune the crystal structure of the resulting black TiO2 nanotubes (Figure 1a and b), as well as tune their electrochemical capacity and conductivity (Firgure 1c). Cyclic voltammetry showed that the polycrystalline black TNTs (TNTsH) have an areal capacitance of approx. 12 mF cm-2, while the oriented TNTs (TNTsCa) 8 mF cm-2. Galvanostatic charge-discharge experiments at a charging/discharging current density of 0.5 mA cm-2 indicated an areal capacitance of 14 mF cm-2 and 12 mF cm-2 for the TNTsH and TNTsCa, respectively. Finally, both hydrogenated TNTs showed an excellent cycling capability, with a capacitance retention of 90% after 10000 charge discharge cycles. These encouraging findings highlight the ability of TiO2 to form stable, metallic-like 1D structures of high surface area for supercapacitor applications.

Figure 1: TEM image of the oriented black TNTs (a), polycrystalline TNTs (b). Inset: XRD patterns of the corresponding structure. (c) Cyclic voltammogram at 100 mV s-1 of the oxidized (TNTsAir) and hydrogenated samples (TNTsH, TNTsCa).

Acknowledgement: Financial support from the Research Council of Norway (EnCaSE project 275058) is acknowledged.

PU8

The effect of crystallite size and donor doping on the conductivity and oxygen absorption of hexagonal RMnO3+δ

Frida Paulsen Danmo¹, Didrik R. Småbråten¹, Sandra H. Skjærvø^1,2,3, Sathya P. Singh¹, Kjell Wiik¹, Dennis Meier¹, and Sverre M. Selbach¹,*

Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
Laboratory for Multiscale Materials Experiments, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland

*E-mail: selbach@ntnu.no

Hexagonal rare earth manganites, RMnO_3+δ (R=Sc, Y, Lu-Ho), are known for being able to accommodate interstitial oxygen (Oi) at intermediate temperatures, making them potential new materials for catalysts chemical looping combustion. The magnitude of δ is greatly dependent on aliovalent doping and crystallite size, but these effects are not well understood. The effect of particle size and dopants on the conductivity and oxygen absorption is imperative to control the properties of RMnO₃. Here we study the changes in oxygen absorption and conductivity of RMnO₃ (R=Y, Ho, Dy) by varying the crystallite size and aliovalent cation doping. Donor doping with Ti4+ promotes oxygen absorption and stabilizes Oi to higher temperatures. The oxidation of RMnO_3+δ nanocrystalline powders with varying crystallite size and donor doping is studied by TGA measurements. From conductivity and Seebeck coefficient measurements, we determine the nature of the conductivity of RMnO₃ in N₂ and O₂ atmospheres at different temperatures. Finally, the experimental results are compared to DFT calculations elucidating the effect of donor doping on the electronic structure and point defect formation energies.

PU9

Key challenges in fabrication of metal-supported proton conducting electrolyser cells

Amir Masoud Dayaghi¹, Marit Stange², Christelle Denonville², Yngve Larring², Per Martin Rørvik², Truls Norby¹

1 Department of Chemistry, SMN/FERMiO, University of Oslo, Gaustadalléen 21, 0349 Oslo, Norway
2 SINTEF, Forskningsveien 1, 0373 Oslo, Norway

Pointing out towards the feasibility of next generation high temperature fuel cells (FCs) and electrolysers(ECs), metals are applied as a support (MS) for proton-conducting cells (PCCs) based on e.g., Y-doped BaZrO₃ (BZY) electrolyte. MSs, particularly ferritic stainless steels, provide high mechanically integrity, and certify fast start-up and stress tolerance. While, PC electrolyte allows lowering the working temperature compared to oxygen ion conducting electrolytes due to their high ionic conductivity. Also, PCs are advantageous yielding dry hydrogen at a lower operating temperature than their counterparts. This alleviates need for purification from water and increases component stability and enables easy integration with waste heat from industry. Due to high refractive properties of BZY, pulsed laser deposition (PLD) is applied to deposit a gas-tight, thin-film layer on top of MS/buffer layer/fuel electrode at low temperature (600-650 °C). Our effort for fabricating MS-PCEC addresses the following issues:

Seeking for alternative fuel electrodes or intermediate buffer layers for MS-PCFCs: The state-of-art Ni containing fuel electrode is not suggested in MSCs as electrodes or intermediate layers due to the coarsening of Ni in high firing temperature (1200-1300 °C) in reducing atmosphere [1, 2].
The La-doped SrTiO3 is not suggested in the vicinity of BZY due heavily reaction of La and Zr resulting the formation insulating La2Zr2O7 phase.
Proton conductor electrolytes usually have low thermal expansion (TEC~8 ppm) compared to MS (~11 ppm) or other candidate intermediate layers. We try to increase TEC to ~10 ppm by adding different dopants (Sr and Ce) on Ba and Zr sites.

Acknowledgements: Financial support from the Research Council of Norway (RCN) through the ENERGIX program is gratefully acknowledged.

References:

Stefan, E., et al., Layered microstructures based on BaZr0. 85Y0. 15O3− δ by pulsed laser deposition for metal-supported proton ceramic electrolyser cells. Journal of Materials Science, 2017. 52 (11): p. 6486-6497.
Dayaghi, A.M., et al., Stainless steel-supported solid oxide fuel cell with La 0.2 Sr 0.8 Ti 0.9 Ni 0.1 O 3− δ/yttria-stabilized zirconia composite anode. Journal of Power Sources, 2016. 324: p. 288-293.

PU10

Influence of ionic species and metal oxide - carbonate phase transformations on the ionic conduction behaviour of Gd-doped ceria - Li₂CO₃/Na₂CO₃composite membranes

V. S. Dilimon, Truls Norby*

Department of Chemistry, University of Oslo, Centre for Materials Science and Nanotechnology, FERMiO, NO-0349 Oslo, Norway

Composite materials consisting of molten carbonates infiltrated in a solid oxide ion conducting matrix (MC-SO) show promising conductivity (> 10−1 S cm−1) even at 600 oC [1]. These membranes have application in molten carbonate fuel cells, which is used for CO₂ separation from the flue gas with simultaneous production of power.
High ambipolar transport of CO2 in such dual phase (solid oxide matrix and liquid molten carbonate) membranes is caused by both carbonate ion transport in the molten carbonate phase and the oxide ion transport in the solid oxide phase as well as solid oxide-liquid interface. Fundamental understanding of the interactions among molten salt, solid oxide and gas phases is very important to optimise the materials composition, fabrication process and operation parameters. In the present work the electrochemical impedance spectroscopy (EIS) is used to study the MC-SO composite membranes under different gaseous compositions of oxygen, carbon dioxide and water vapour at different temperatures. The aim is to understand the role of temperature and charge carriers on bulk, interfacial (between oxide grains, and between oxide and carbonate interface), and electrode processes. Gd-doped ceria (GDC) based composite membranes prepared by the infiltration of Li2CO3-Na2CO3 eutectic molten phase in a pre-sintered porous GDC matrix are used for the study. EIS measurements in a range of temperatures, from below to above the melting point of carbonate phase, are carried out. The fitting of EIS results with suitable electrochemical equivalent circuit models gives information about various physico-chemical interactions between oxide grains, and between solid oxide and carbonate (both in its solid and liquid state) interface.

Reference:

J. R. S. Pereira, S. Rajesh, F. M. L. Figueiredo and F. M. B. Marques, Composite electrodes for ceria-carbonate intermediate temperature electrolytes. Electrochimica. Acta 90 (2013) 71.

Acknowledgement: The authors wish to acknowledge the financial support from Project M-ERA.NET Call 2016.

PU11

Novel Molten/solid Composite Oxygen Transport Membranes for CO2 Capture

Linn Katinka Emhjellen¹*, Tor S. Bjørheim¹, Marie-Laure Fontaine², Zuoan Li², Truls Norby¹

1 Centre for Materials Science and Nanotechnology, University of Oslo, Norway
2 SINTEF Industry, Oslo, Norway
*l.k.emhjellen@smn.uio.no

The development of high flux oxygen transport membranes (OTMs) operating at intermediate temperatures is imperative for improving energy efficiency of oxygen combustion in CCS integrated power plants. Due to the lower energy barrier for oxide ions to move in a liquid as compared to a solid, novel OTMs consisting of a solid phase and a molten oxide such as ZrO2−V2O5 based composites have shown enhanced oxide ion conductivity when annealed above the eutectic point of the system [1-3]. By utilizing conduction channels present either through the bulk of the molten phase and/or at the molten/solid interface, the aim is to present a novel generation of OTMs designed as composite systems exhibiting improved oxygen flux (~2
mL/min·cm2) and long-term stability at intermediate temperatures (<600°C). In this work, we investigate the defect chemistry and transport mechanisms in a ZrV2O7-30mol%V2O5 molten/solid composite through electrochemical measurements and first principles calculations.

Fig.1: Various membrane designs with a) ambipolar transport in a solid MIEC membrane, b) enhanced oxide ion transport in a molten/solid composite membrane (macroporous solid phase) and c) increased oxygen flux in a molten/solid composite membrane with functional interfaces (micro- or mesoporous solid phase).

Acknowledgement: This work has been supported by the Research Council of Norway (RCN) through the MOC-OTM (268450) project.

References:

Belousov, V.V., Metallurgical and Materials Transactions A, 2014. 45(10): 4257-4267.
Belousov, V.V., Accounts of Chemical Research, 2017. 50(2): 273-280.
Belousov, V.V., Ionics, 2016. 22(4): 451-469.

PU12

Point Defects in Monolayer MoS₂

Christian Fleischer

Defect chemistry has given the possibility to control and tune properties to obtain better functional bulk materials. In comparison, and despite the recent interest and prospects of two dimensional materials, their defect chemistry remains mainly unexplored. We believe that an understanding of the influence of the dielectric environment on the defect chemistry and properties is crucial for further developing new and superior 2D materials. Here, we present results from our computational work on selected point defects in monolayer MoS2. Investigated defects comprises molybdenum and sulphur vacancies in
addition to hydrosulfide on sulphur site and more.

PU13

DFT study of a stable junction between p-type NiO and n-type ZnO

Emil Frøen, Truls Norby

Dept. Chemistry, Univ. Oslo, FERMiO, Gaustadalléen 21, NO-0349 Oslo, Norway

Modern p-n junctions are typically constructed from doped silicon semiconductors, by placing two differently doped silicon semiconductors in direct contact with one another. This forms a low entropy system where the dopant ions have a tendency to diffuse across the junction to reach an equilibrium state. The p- and n- type dopants will thus increasingly cancel each other’s effects in the semiconductor over its lifetime, gradually blurring the junction until the point of complete Under low temperature conditions, this unstable initial state does not cause problems for practical usages, as the process of interdiffusion is kinetically hindered to such an extent the blurring of the junction will not occur to a significant extent over the expected usage timeframe.

At high temperatures, however, the rate at which the p- and n- type dopants will diffuse across the interface and into the oppositely doped semiconductor becomes non-trivial. For high temperature applications such as thermoelectric generation, this renders silicon-based semiconductors unsuitable.

A possible solution to this issue is the use of coexistent oxide semiconductors, where the two semiconductors of a p-n junction are in thermodynamic equilibrium with each other. Utilizing metal oxides which form a partly soluble system, such a p-n junction would have no interdiffusion and could theoretically remain operational indefinitely.(1)

This project aims to perform a computational DFT analysis on one potential pair of candidates for such an application; nickel oxide and zinc oxide, with a focus on studying the electronic properties of the junction between these oxides, such as the band structure. The properties of the interaction of various possible pairs of crystal planes between the two compounds will be investigated, particularly the experimentally observed interfaces.(2) Furthermore, the project aims to explore if any special electronic effects occur under the unique environment.

References:

Desissa TD, Schrade M, Norby T. Electrical properties of a Li-doped NiO and Al-doped ZnO p-n heterojunction. Prep.
Ma MJ, Lu B, Zhou TT, Ye ZZ, Lu JG, Pan XH. Orientation dependent band alignment for p-NiO/n-ZnO heterojunctions. J Appl Phys. 2013 Apr; 113 (16):4.

PU14

Search for functional materials demonstrating Giant Magnetostructural Phase transition for Solid State Refrigeration applications

Nicolai Hauffen, Bruno Gonano, Dipankar Saha, Susmit Kumar, Anja Olafsen Sjåstad, Helmer Fjellvåg

Department of Cemistry, University of Oslo

Functional magnetic materials demonstrating large discontinuity in magnetization and associated latent heat while transitioning through a First Order Magnetic Transition (FOMT) are highly sought after for applications in the field of solid state refrigeration that take advantage of the (inverse) magnetocaloric effect (MCE) []. It is expected that MCE systems will have transformative
improvements in heating / cooling technologies by means of both being energy efficient and environmentally friendly. After decades of research focusing solely on Second Order Magnetic Transition (SOMT) in Gd, EuO and Fe and failing to achieve substantial MCE effect, the research is presently focused mainly on FOMTs of magneto-structural (MS) and magneto-elastic (ME) flavours.

Examples of MS are MnAs, Gd5(Si, Ge)4, MnCoGe systems which show simultaneous change in crystal symmetry, whereas, for ME are Fe2P, FeRh, and Gd5(Ge, Sb)4 that show no change in symmetry []. Here we present our work on rare-earth element free MS based FOMT intermetallic MnAs system, where we have carried out substitution on both A- and B-sites with (A = Cr, Ni) and (B= P and Sb) respectively. It is predicted that such substitutions should both lower the reported FOMT
temperature from 318 K and enhance MCE effect from existing entropy change, ΔS of 30 J/K kg at 5T []. Samples were prepared using solid-state synthesis, as well as Spark Plasma Sintering (SPS) process. To elucidate and understand in-depth the root-cause of FOMT in MnAs intermetallic systems, thorough crystal structure, magnetic, electronic and thermodynamic characterization were carried out taking advantage of in-house (RECX and PPMS) and central facilities. Here we show the results from such characterizations.

PU15

Ionic, protonic and electronic conductivity in Li7La3Zr2O12-based materials

Kolding, J., Sartori, S., Norby, T.

Department of Cemistry, University of Oslo

Modern society is completely dependent on electricity. With the constant evolution of personal electronics, as well as the fast development of electric vehicles, the demand for batteries has exploded. Customers want small, but still powerful batteries which can power their devices for as long as possible. A weakness of today’s Li-ion batteries is that they use a liquid organic electrolyte. This is rather unstable, and leakage in the battery can lead to fires, which has been seen recently with some smart phones catching fire. The solution to this may be a solid electrolyte. There are several suggestions to materials for this, like LiSICON, perovskite- and Li3N-type materials. In this work we are looking at the garnet-type electrode Li₇La₃Zr₂O₁₂ (LLZO). This garnet has shown promising results when it comes to conductivity, showing values as high as 3.1 × 10−4 S cm−1 at 25 °C. [1] The samples in this work were prepared by solid-state synthesis, with sintering at >1100°C for 12 hours, to produce the more conductive cubic LLZO phase. [2] By XRD we have seen that there are both cubic and tetragonal phases in our samples. We work, at present, with making samples of higher density and with more cubic phase, possibly by doping the garnet with Al. [2] We will measure the conductivity of the samples and focus on interpretation in defect chemical terms. Furthermore, we aim to analyze the resistive effect of grain boundaries and to determine contributions from electronic species under oxidizing and reducing conditions as well as protonic species originating from traces of water vapor.

References:

Li, Yand, John B. Goodenough (2012) Ionic distribution and conductivity in lithium garnet Li₇La₃Zr₂O₁₂. Journal of Power Sources, volume 209, pp. 278-281. Available from doi: 10.1016/j.jpowsour.2012.02.100 [Accessed 31.08.18]
Rangasamy, Ezhiyl, Jeffrey Sakamoto (2012) The role of Al and Li concentration on the formation of cubic garnet solid electrolyte of nominal composition Li₇La₃Zr₂O₁₂. Solid State Ionics, volume 206, pp. 28-32. Available from doi: 10.1016/j.ssi.2011.10.022 [Accessed 31.08.18]

PU16

Phosphites as precursors in thin film synthesis. Using LiPO₄ as cathode coating in Li-ion batteries.

Kristian B. Kvamme, Amund Ruud, Kristian Weibye and Ola Nilsen.

Centre for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, N-0315 Oslo, Norway.
E-mail: k.b.kvamme@smn.uio.no

Phosphate based materials show great promise as electrolytes in solid state batteries. The ideal solid state electrolyte should be thin and uniform. For these reasons Atomic layer deposition (ALD) has been suggested as a good synthesis route for solid state electrolytes. Phosphate synthesis in ALD usually includes fully oxidised phosphate precursors. In this work a new route for synthesising phosphorous based material using ALD is demonstrated. Phosphite precursors have been used for the synthesis of LiPO₄ and AlPO₄ materials. This is done by replacing phosphate precursors with phosphite precursors in established ALD synthesis routes. Furthermore the LiPO₄ product has been deposited as a coating layer onto LiFePO₄ cathodes to improve kinetics and low current density cycling performance. We have shown that there is indeed an improvement at coating thicknesses of 1 nm or less. The materials themselves have been characterised using XPS and XRF for composition analysis, spectroscopic ellipsommetry for thickness as well as Cyclic voltammetry and Galvanostatic cycling for electrochemical analysis.

PU17

Enzyme-assisted Catalysis on Black Titania Electrodes

X. Liu,¹* A. Chatzitakis,¹ P. A. Carvalho,² P. H. Backe,^3,4 M. Yang,^3,4, M. Bjørås,^3,4 T. Norby¹

Department of Chemistry, University of Oslo, FERMiO, Gaustadalléen 21, NO-0349 Oslo, Norway
Materials Physics, SINTEF, Forskningsveien 1, NO-0314 Oslo, Norway
Department of Microbiology, Oslo University Hospital, Norway
Department of Medical Biochemistry, University of Oslo, Norway

The widespread use of fuel cells and water splitting devices for energy generation and storage is restricted by the dependence on noble metal catalysts. There is a tremendous need for the development of efficient electrocatalysts made of Earth-abundant elements. Taking example from nature, hydrogenases are metallo-enzymes that catalyze the reversible reaction of H₂ to protons and electrons, with an activity comparable to that of Pt. The reaction sites of some of these hydrogenases contain Fe, which are known as [FeFe]-Hydrogenases (HydA). This work will address a new class of electrodes for enzyme attachment and bio-assisted catalysis, which is developed based on the hydrogenated TiO2 or black titania. Black titania nanotubes ensure high electronic conductivity, hydrophilicity and high surface area. The versatile morphology of tubes (tube length, crystal orientation and pore diameter etc.) can provide shielding of HydA, which is an O2-sensitive enzyme, as well as encasing for improved attachment and functionalization. Bio-TEM will be used to image the enzyme on the substrate, while a high aspect ratio and highly conducting oxide nanomaterial will shield the enzyme from the atmospheric oxygen and provide at the same time electronic conduction. Based on experimental findings, density functional theory (DFT) based calculations can be utilized to probe the catalytic reaction sites on the HydA and address the interaction between enzymes and titania in detail. The novel bioelectrode will be employed in a system of artificial photosynthesis and generation of solar fuels by simultaneous water splitting and CO₂ capture and utilization.

Figure 1. The EnCaSE concept: The structure and reducing conditions in the nanotube provides protection from the oxygen, while the lighter and smaller hydrogen can escape.

Acknowledgement: Financial support from the Research Council of Norway EnCaSE project 275058 is acknowledged.

PU18

Preparation and characterization of Ru/CeO2 catalysts for electrically enhanced ammonia synthesis

Quanbao Ma, Diamanta Ibishi, Truls Norby

University of Oslo, Department of Chemistry, Centre for Materials Science and Nanotechnology, FERMiO, Gaustadalléen 21, NO-0349 Oslo, Norway
* quanbao.ma@smn.uio.no

Ammonia is an important compound that is widely used as a raw material for chemical fertilizers, fibers, refrigerants, etc. Because of its high hydrogen content, recently ammonia has been considered as a hydrogen carrier [1]. The Haber-Bosch process is currently the main method for ammonia synthesis. But the process is conducted at high pressures and high temperatures ( ̴ 773 K) due to its thermodynamic and kinetic limitations [2]. However, the ammonia can be synthesized over heterogeneous catalysts by surface proton hopping at a low temperature, which has been confirmed to be highly efficient, since N₂ dissociative adsorption is markedly promoted by the application of the electric field [3].

Among Fe, Ru, Re, Co and other transition metals based catalysts, Ru/CeO₂ is considered as one of the most effective and stable catalysts for ammonia synthesis [4]. It was found that partially reduced CeO_2−xcan donate electrons to Ru, which is useful to promote the cleavage of N ≡ N triple bonds. The Ru/CeO₂ catalysts with Ru loading of 1, 3 and 5 wt % have been synthesized using a deposition-precipitation method and then characterized by XRD, SEM, EDS, XPS, etc. The catalytic activity tests for ammonia synthesis are performed with and without the electric field. The study on ammonia synthesis is still on going.

Acknowledgement: the financial support of this work by Norwegian Research Council (Project “COLD” No. 280495) is gratefully acknowledged.

References:

U.B. Demirci and P. Miele, Energy Environ. Sci, 4 (2011) 3334.
H. Stoltze and J.K. Nerskiv, Phys. Rev. Lett 55 (1985) 2502.
R. Manabe, H. Nakatsubo, et al., Chem. Sci. 8 (2017) 5434.
B. Lin, Y. Liu, et al., Ind. Eng. Chem. Res., 57 (2018) 9127.

PU19

Self-assembled Ni_0.98Li_0.02O and Zn_0.98Al_0.02O composite interface for thermoelectrics

Reshma Krishnan Madathil, Temesgen D. Desissa and Truls Norby

Centre for Materials Science and Nanotechnology (SMN), Department of Chemistry, University of Oslo. FERMiO, Gaustadalléen 21, NO-0349 Oslo, Norway

Thermoelectric generators (TEGs) offer flexible and robust conversion of waste heat to electricity. TEGs consist of p- and n-type semiconductors connected electrically in series and thermally in parallel: The temperature gradient across the TEG results in the generation of thermoelectric power due to the Seebeck effect [1].

Thermoelectric (TE) materials candidates include chalcogenides, silicides, carbon compounds, metal oxides, clathrates, and alloys. Among these, oxides have been rapidly developed in the last decade because of potential advantages over non-oxides in terms of chemical and thermal stability at high temperatures. One of the factors limiting the ideal performance of a conventional oxide TEG arises from the use of metal interconnects to ensure ohmic contact, which are vulnerable to inter-diffusion, cracking, evaporation, and oxidation. To overcome these challenges, Span and co-workers proposed the use of a direct p-n junction [2], despite the expected high electrical contact resistance. Using a composite interconnect from the desired p- and n-type oxide material at the interface (p-c-n) can increase the effective contact area and reduce the electrical contact resistance.

p-type NiO and n-type ZnO are promising oxide materials for high-temperature thermoelectrics [3, 4]. In the present work, we investigate a composite consisting of Ni_0.98Li_0.02O and Zn_0.98Al_0.02O, prepared by a citric acid sol-gel combustion method to obtain a self-assembled composite [5]. X-ray diffraction and scanning electron microscopy confirm the presence of separate NiO and ZnO phases. Current-voltage characteristic curves of direct planar p-n and composite p-c-n junctions were investigated, with the latter showing less resistive behaviour, attributed to the increased effective contact area.

References

Seebeck, T.J., "Ueber die magnetische Polarisation der Metalle und Erze durch Temperaturdifferenz". Annalen der Physik, 1826. 82 (3): p. 253-286.
Span, G., et al. Thermoelectric Power Conversion using Generation of Electron-Hole Pairs in Large Area p-n Junctions. in 2006 25th International Conference on Thermoelectrics. 2006.
Woosuck Shin and Norimitsu Murayama, Li-Doped Nickel Oxide as a Thermoelectric Material. Japanese Journal of Applied Physics, 1999. 38 (11B): p. L1336.
T. D. Desissa, M.S., T. Norby, Electrical properties of a p-n heterojunction of Li-doped NiO and Al-doped ZnO for thermoelectrics. Submitted 2018.
Chen, K.J., et al., The crystallization and physical properties of Al-doped ZnO nanoparticles. Applied Surface Science, 2008. 254 (18): p. 5791-5795.

PU20

Mechanistic study by impedance spectroscopy of the positrode reaction on proton ceramic electrochemical cells

Madeeha Khalid Pedersen, Ragnar Strandbakke, Truls Norby

Department of Chemistry, University of Oslo, SMN, FERMiO, Gaustadalléen 21, NO-0349 Oslo, Norway

In Proton Ceramic Fuel Cells (PCFCs) hydrogen oxidizes at the anode (negatrode) to form protons, and the electrolyte conducts protons to the cathode (positrode) where they react with oxygen to form water vapour. Proton Ceramic Electrolyzers (PCEs) performs the reverse reaction, forming hydrogen and oxygen from steam. Such Proton Ceramic Cells (PCCs) have several potential advantages over other types of electrochemical cells, but materials and processes are less optimised and performance and lifetime need to be improved.

In particular, the exchange between oxygen gas, protons, and water vapour

O₂ (g) +4H⁺ +4e^- <-> 2 H₂O (g)

is limited by lack of stable mixed proton and p-type electronic conducting positrode materials (MPECs), and we know little about the rate limiting elementary steps and microstructural sites involved.

As part of our on-going work to address these matters, we here study a ceramic point electrode made of the double perovskite BaGd_0.8La_0.2Co₂O_6-δ (BGLC) on a thick electrolyte of BaZr_0.7Ce_0.2Y_0.1O₃, with Pt counter and reference electrodes. Impedance spectroscopy is used to delineate the electrode response in ohmic (electrolyte), charge transfer, and mass transfer contributions.

Variations in temperature, pH₂O, and pO₂ allow modelling of these contributions further into partial protonic, oxide ionic, and electronic currents. pH₂O and pO2 dependencies are furthermore analysed with regard to rate limiting availability of reactant species and sites. Pre-exponential factors are interpreted in terms of effective area and length of reaction zones, and compared with the area and circumference of the point electrode footprint on the electrolyte, as analysed by electron microscopy.
The knowledge obtained will be used to suggest improvements in electrode composition and microstructure for better performance of operating PCECs.

PU21

Conductivity and defect structure of ferric tungstate

Raphael Schuler, Truls Norby, Helmer Fjellvåg

Centre for Materials Science and Nanotechnology (SMN), University of Oslo, Sem Sælands vei 26 Kjemibygningen, 0371 Oslo- Norway

Ferric tungstate Fe₂WO₆ has gained increased interest as a cheap and abundant semiconducting oxide over the last decades. Its surprisingly high conductivity, chemical and thermal stability, and semiconducting properties made it an interesting candidate for e.g. photoelectrode material or high temperature thermoelectric.(1) With both n- and p-type conductivity reported, the nature of the charge carriers is still debated.(2) Its defect chemistry and thermoelectric properties are mainly unexplored. To gain a better understanding of the conductivity mechanisms and defect chemistry, we combine conductivity and Seebeck-coefficient measurements, both in dependence of temperature and Oxygen partial pressure. We herein try to give new insight in the defect chemistry and conducting behavior of Fe₂WO₆ at elevated temperatures.

References

F.F. Abdi et.al. , J. Phys. Chem. C, 2017, 121 (1), pp 153–160
Bharati R., Singh R.A., J. Mat. Sci. 1981, 16 (2), pp 511-514

PU22

Verification of hierarchical porosity in CuSAPO-34 by in situ XAS, N2 adsorption measurements and NOx removal

Guro Sørli,Dragos Stoian†, Magnus Rønning§,Karina Mathisen

*Department of Chemistry, §Department of Chemical Engineering, Norwegian University of Science and Technology, 7491 Trondheim, Norway
†Swiss Norwegian Beam Lines, European Synchrotron Radiation Facility, Grenoble, France"

guro.sorli@ntnu.no

Removal of NOx from combustion processes made headlines in 2015 following the so-called “diesel-gate”, showing that new development and research concerning deNOx technology is still highly topical1. Copper containing, microporous SAPO-34 has shown great activity concerning selective reduction of NOx (NH3-SCR and HC-SCR) and may be thought of as a new possible catalyst for NOx removal from internal combustion engines2-6. These catalysts are known to suffer from instability concerning copper addition and deactivation due to coking. The goal of this project is to solve these challenges by introducing mesopores to create so-called hierarchical CuSAPO-34 to relieve the mass transfer issues.

Different structure directing agents have been used to obtain hierarchical CuSAPO-34 and comparisons have been made with the conventional microporous analogue. In-situ XAS data has been recorded at the Swiss-Norwegian Beam Lines (SNBL, BM 31) at the ESRF in Grenoble, France in order to obtain information about the reducibility and size of copper clusters in the samples. Multivariate curve resolution (MCR) analysis has been utilised to obtain reduction profiles of copper. Results from in situ XAS analysis have been correlated with BET surface area and BJH pore size distribution measurements. In the presence of copper, the structure directing agent (SDA)-pair diethylamine (DEA) + tetraethylenepentamine (TEPA) yields a high degree of mesoporosity in CuSAPO-34, whereas the SDA-constellation morpholine (MOR) + TEPA + cetyltrimethylammonium hydroxide (CTAOH) yields mostly micropores. The pore distribution show a large number of mesopores ranging from 30 – 200 Å in the former, correlating with 100 m2/g external/meso area from the t-plot, not present in the sample made with CTAOH. The introduction of mesopores greatly affects the reducibility of copper during temperature programmed reduction (TPR) by H2 (75%), as copper is completely reduced at 490°C in the sample containing mesopores, but 20% CuI-O remains in the microporous sample, even at 700°C. The introduction of mesopores is again reflected in the obtained copper particle sizes from EXAFS analysis, as the mesoporous CuSAPO-34 hosts clusters of 14 Å (NCu-Cu = 8) whereas they are found to be 9 Å (NCu-Cu = 6) in the sample with mainly micropores (the method of corrected multiplicities were employed for the latter sample).

Employing HC-SCR deNOx as a model reaction, the introduction of mesopores greatly improves the NOx conversion over the whole temperature range (275- 500°C), but especially in the low temperature range (<375°C). Whereas the hierarchical CuSAPO-34 made with DEA-TEPA becomes active at 325°C reaching maximum conversion of 67% at 400°C, the microporous becomes active at 375°C and reaches maximum conversion of 52% at 450°C. Clearly, altering the porosity of CuSAPO-34 has great impact on chemical and catalytic behaviour of the zeotype.

References

R. Hotten, Journal, 2015.
U. Deka, I. Lezcano-Gonzalez, S. J. Warrender, A. Lorena Picone, P. A. Wright, B. M. Weckhuysen and A. M. Beale, Microporous and Mesoporous Materials, 2013, 166, 144-152.
T. Jakobsen, Master Thesis, NTNU, 2014.
K. A. Lomachenko, E. Borfecchia, C. Negri, G. Berlier, C. Lamberti, P. Beato, H. Falsig and S. Bordiga, Journal of the American Chemical Society, 2016, 138, 12025-12028.
M. Moliner, C. Martínez and A. Corma, Chemistry of Materials, 2014, 26, 246-258.
D. Wang, L. Zhang, K. Kamasamudram and W. S. Epling, ACS Catalysis, 2013, 3, 871-881.

PU23

Solid-state tandem photoelectrochemical cell for wet air electrolysis and hydrogen production

K. Xu,¹ E. Vøllestad,² Q. Ruan,³ J. Tang,³ A. Chatzitakis,¹* T. Norby¹

Department of Chemistry, University of Oslo, SMN, FERMiO, Gaustadalléen 21, NO-0349 Oslo, Norway
SINTEF Industry, Forskningsveien 1, NO-0373 Oslo, Norway
Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, U.K.

Tel.: +47-22840693
a.e.chatzitakis@smn.uio.no

In this work, a solid-state photoelectrochemical (SSPEC) cell is developed with the use of polymer proton conducting membranes as the electrolyte, which replaces the aqueous ones [1]. The aim is to design monolithic and ease-deployable devices, minimize the distance between the electrodes and produce hydrogen in rural or areas where grid infrastructure and water sources are scarce or abscent. In addition, such devices must be made of earth-abundant materials and towards this direction, we replaced the traditionally used Pt in the cathode with an earth-abundant 2D photocathode, g-C3N4, forming a tandem photocatalysts’ configuration.

The SSPEC cells were run under purely gaseous conditions, where the anode was supplied with air of 80% relative humidity and the cathode with argon. The tandem configuration showed a steady-state photocurrent density, which is significantly higher compared to the cell with Pt as the cathode (Figure 1 left). The mechanism of operation is discussed in view of recent advances in surface proton conduction in absorbed water layers [2], as well as in the additional built-in voltage supplied by the photocathode (Figure 1 right). The presented SSPEC cell provides a new way towards systems of artificial photosynthesis, where the only requirements to make hydrogen are humidity and sunlight.

Figure 1: Chronoamperometry at 3 different applied voltages. Light on period, 180 s and light off, 20 s (left). The concept of water vapour splitting and hydrogen production in a tandem-SSPEC cell (right).

References

K. Xu, A. Chatzitakis, T. Norby, Photochem. Photobiol. Sci., 16 (2017) 10-16.
S.Ø. Stub, E. Vøllestad, T. Norby, J. Phys. Chem. C, 121 (2017) 12817-12825.

Acknowledgement: Financial support from the Research Council of Norway (CO2BioPEC project 250261 and PH2BioCat project 239211) is acknowledged.

PU24

Pt_100-xRh_x/Al₂O₃ catalysts for ammonia oxidation at intermediate temperatures

P. Dhak^a, K. I. Skau^b, D. Waller^b, J. Skjelstad^c, H. Fjellvåg^a, A. O. Sjåstad^a

a Centre for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo, Norway
b Yara International ASA, Yara Technology Centre, P.O. Box 1130, N-3905 Porsgrunn, Norway
c K. A. Rasmussen, Strandvegen 165, 2316 Hamar, Norway

Selective catalytic reduction (SCR) is currently used in the abatement of NO_x in heavy vehicles, marine engines and stationary power plants where the reductant ammonia (NH₃) converts NO completely into N₂and H₂O. In this process, the excess NH₃ emitted has potentially harmful effects; thus, its emission control is very urgent. The most promising and widely used technology for solving this NH3 pollution is the selective catalytic oxidation (SCO) of NH₃ (SCO-NH₃) to produce N₂ and H₂O [1-3]. In this study, well-defined 8.5 – 11.5 nm sized Pt_100-xRh_x (0 ≤ x ≤ 100) alloy nanoparticles (NPs) were synthesized by the polyol method [4], and converted to NPs/γ-Al₂O₃ catalysts using our established procedure reported by Zacharaki et al. [5]. The catalysts were tested for SCO-NH₃ in a quartz tubular fixed bed reactor (FBR) at temperature between 175 to 410 °C in a 5% O₂/500 ppm NH₃/intert gas mixture. The free standing NPs were characterized by powder X-ray diffraction, (high-resolution) transmission electron microscopy (TEM) and scanning TEM-energy dispersive X-ray spectroscopy (STEM-EDX) to confirm phase purity, average particle size and element distribution in the bimetallic compositions, respectively4. The metal loading and distribution of NPs on the γ-Al₂O₃ support were deteremined through inductively coupled plasma mass spectrometry (ICP-MS) and high angle annular dark field (HAADF)-STEM. A carefull analysis of the catalytic performance tests showed a complex nature. The Pt based NPs appeared to be much more active than the Rh counterpart. On the contrary, a trend of increasing N₂ selectivity was noticed with increasing Rh concentration in the bimetallics NPs and simultaniously, the unwanted N₂O and NO_x formation was decreased.

Keywords: Pt-Rh/Al₂O₃NH₃ Slip Catalyst; Polyol Method; Ammonia Oxidation.

References:

F. Wang, J. Ma, G. He, M. Chen, C. Zhang, H. He, ACS Catal. 8 (2018) 2670-2682
C. M. Hung, Advanced Materials Research, 160-162 (2011) 1285-1290
C. M. Hung, W. L. Lai, J. L. Lin, Aerosol and Air Quality Research, 12 (2012) 583-591
S. Bundli, P. Dhak, M. Jensen, A. E. Gunnæs, P. D. Nguyen, H. Fjellvåg, A. O. Sjåstad, J. Alloy and Compd. (under revision) 2018
E. Zacharaki, P. Beato, R. R. Tiruvalam, K. J. Andersson, H. Fjellvåg, A. O. Sjåstad, Langmuir, 33 (2017) 9836-9843

PU25

Conductivity of polymer-ceramic composite membranes at high T and p(H2O) using a novel PEEK sample holder

A. Chatzitakis^1*, S.C. Simonsen¹, M.L. Fontaine², M.S. Thomassen², I. Lorentzen³, T. Norby¹

1 Department of Chemistry, University of Oslo, SMN, FERMiO, Gaustadalléen 21, NO-0349 Oslo, Norway
2 SINTEF Industry, Forskningsveien 1, NO-0373 Oslo, Norway
3 NORECS AS, Gaustadalléen 21, NO-0349 Oslo, Norway

Tel.: +47-22840693

a.e.chatzitakis@smn.uio.no

Operating proton exchange membrane (PEM) fuel cells at temperatures above 100°C has advantages such as limited cathode electrode flooding, improved electrocatalyst lifetime, reduced catalyst loading, and increased efficiency and simplicity of the system due to better energy management [1]. However, the high temperature compromises mechanical integrity, hydration, and proton conductivity of PEMs such as Nafion®. One approach to remedy these problems is to introduce inorganic fillers, for example silica. This may reduce hydrogen crossover and stabilise the membrane mechanically during otherwise critical heating and dehydration, while mechanisms for increased water retention at temperatures above 100°C are debatable.

In this work we present a new sample holder and atmosphere control system for high throughput measurements of PEM conductivity at high temperatures and partial pressures of water vapour, applied to cast composite films of PEMs with various silica micro- and nanopowder fillers.

A 4-probe polyether ether ketone (PEEK) stage (Figure 1) with replaceable gold wire contacts, provisions for reversible hydration, and accurate temperature control has been developed for spring-loading and enclosure in a ProboStat™ sample holder with heated base unit. A tailor-made humidifying system (HumiStat, NORECS, Norway) is used to supply gas with controlled high steam contents.

The protonic conductivity is measured vs T and pH2O and interpreted in terms of hydration and protonic mobility, as well as stability. With well-controlled and reproducible conditions and measurements, the effects on conductivity of the silica fillers used in this study, so far are small.

Figure 1. Left: Design sketch of sample stage with gold wire contacts and electrode connections mounted in a ProboStat™ support tube. Right: Photograph of the actual PEEK component with contact terminals.

Reference

R. Devanathan, Energy & Environmental Science 1 (2008) 101-119

PU26

DFT study on proton uptake in BaFeO_3-x

Maximilian Felix Hoedl, Rotraut Merkle, Eugene Kotomin, Joachim Maier

Max Planck Insitute for Solid State Research

In this poster the results of first-principles DFT+U calculations on the perovskite material BaFeO3 are presented. The material belongs to the class of mixed ionic and electronic conductors and is used as model material to study the interplay between the complex electronic structure and the defect chemistry in the material.

The electronic density of states is discussed with emphasis on the hybridization effects between the oxygen 2p levels and the iron 3d levels. In addition, the formation of multiple oxygen vacancies as well as the formation of protonic defects is investigated. The incorporation of protons leads to the formation of distinct O-H bonding states visible in the projected density of states.

Det 21. Landsmøte i kjemi

Posters og Posterabstracts

Disse faggruppene har postere:

PK - Katalyse

PK1

Selective Oxidation of Methane to Methanol Over Cu-loaded SAPO-34 Catalysts

Karoline Kvande

PK2

Investigation of the effect of different activation conditions on the catalytic activity of Pt-functionalized UiO-67

Bjørn Gading Solemsli*, Emil Sebastian Gutterød, Unni Olsbye

PK3

Influence of the pressure and the reaction flow regime on the conversion of methanol to aromatics.

Irene Pinilla-Herrero1,2*, U.V.Mentzel2, F.Joensen2, K.P. Lillerud1, U. Olsbye1, Stian Svelle1, Pablo Beato2

PK4

The use of UiO-type MOFs in gas phase Soai reactions

Giuseppe Rotunno, Gurpreet Kaur, Mohammed Amedjkouh, Karl Petter Lillerud, Unni Olsbye

PK5

A DFT study on the reaction mechanism of methane to methanol direct conversion via Cu-exchanged chabazite catalyst.

Carlo Buono1, Pablo Beato2, Silvia Bordiga1,3, Unni Olsbye1 and Stian Svelle1*.

PK6

Bimetallic CuPt and CuPd nanoparticles prepared by Microwave Synthesis for CO2 conversion to useful fuels

Maria Kalyva, Evgeniy Redekop, Giorgios Kalatzopoulos, Anette Eleonora Gunnæs , Spyros Diplas, Unni Olsbye

PK7

Real-time regeneration of a working zeolite monitored via operando space-resolved X-Ray diffraction

Georgios N. Kalantzopoulos*, Daniel Rojo Gama, Dimitrios K. Pappas, Karl Petter Lillerud, Unni Olsbye, David S. Wragg and Stian Svelle.

PK8

Ethene dimerization with metal-organic framework (MOF) functionalized with Ni(II) and bipyridine

Mustafa Kømurcu1, Andrea Lazzarini1, Gurpreet Kaur1, Silvia Bordiga2, Unni Olsbye1*

PK9

Synthesis and characterization of gold(I) NHC complexes suitable as FEBID precursors

Cristiano Glessi1*, Jakub Jurczyk2,3, Ivo Utke2 and Mats Tilset1

PK10

Production of high surface area zirconium oxides through thermal metamorphosis of metal organic frameworks.

Christopher W. Affolter, Evgeniy A. Redekop*, Sigurd Øien-Ødegaard, Maria E. Kalyva, Emil S. Gutterød, Karl-Petter Lillerud, and Unni Olsbye

PK11

Magnetic properties of [NpO2(dpc)2]2- in solid and in solution

Julie Héron1, Hélène Bolvin2*

PK12

Biomimetic copper complexes for incorporation into MOFs

Isabelle Gerz, Unni Olsbye, Mats Tilset, Mohamed Amedjkouh

PK13

A Niobia-Supported Iridium-Based Catalyst for Deoxygenation of Lignin-Derived Model Compounds

Simen P. Følkner, Raju Dey, Giovanni Occhipinti, Vidar R. Jensen*, Erwan Le Roux*

PM - Makromolekyl- og kolloidkjemi

PM1

Liposomes as a model system for the study of surface active peptides

V.A. Bjørnestad, J.E. Nielsen and R. Lund

PM2

Interactions between Anionic Surfactants and Polymeric Micelles: stability and solubilisation kinetics

Synne Myhre(a), Matthias Amann(a), Lutz Willner(b), Kenneth D. Knudsen(c) and Reidar Lund(a)

PM3

Thin film breakage in the interphase region formed between two interacting drops.

Enrico Riccardi

PU - Uorganisk kjemi og materialkjemi

PU1

In situ prepared epoxy nanocomposites for high voltage insulation

Mohammed Mostafa Adnan

PU2

Investigation of characterization methods for new porous functional materials

Daniel Ali*, Hilde Lea Lein†, Karina Mathisen*,

PU3

Double perovskite oxides as electrocatalysts for the oxygen evolution reaction

H. Andersen, A. Chatzitakis, R. Strandbakke,* T. Norby

PU4

Pyrolysis of silanes and silane mixtures – kinetic modelling and experiments using a benchtop reactor

Anjitha S G, T. J. Preston, G. Marie Wyller.

PU5

Formation and characterisation of a Cu2O – ZnO p–n–Junction

K. G. Both, C. Bazioti, T. S. Bjørheim, O. M. Løvvik, T. Norby

PU6

Amorphous FePO4 in thin film batteries

Anders Brennhagen, Ola Nilsen

PU7

Black titania nanotubes with tunable crystal orientation for supercapacitors

A. Chatzitakis,1* X. Liu,1 P. A. Carvalho,2 M. Norderhaug Getz,1 T. Norby1

PU8

The effect of crystallite size and donor doping on the conductivity and oxygen absorption of hexagonal RMnO3+δ

Frida Paulsen Danmo1, Didrik R. Småbråten1, Sandra H. Skjærvø1,2,3, Sathya P. Singh1, Kjell Wiik1, Dennis Meier1, and Sverre M. Selbach1,*

PU9

Key challenges in fabrication of metal-supported proton conducting electrolyser cells

Irene Pinilla-Herrero^1,2*, U.V.Mentzel², F.Joensen², K.P. Lillerud¹, U. Olsbye¹, Stian Svelle¹, Pablo Beato²

Carlo Buono¹, Pablo Beato2, Silvia Bordiga^1,3, Unni Olsbye¹ and Stian Svelle¹*.

Bimetallic CuPt and CuPd nanoparticles prepared by Microwave Synthesis for CO₂ conversion to useful fuels

Mustafa Kømurcu¹, Andrea Lazzarini¹, Gurpreet Kaur¹, Silvia Bordiga², Unni Olsbye^1*

Cristiano Glessi^1*, Jakub Jurczyk^2,3, Ivo Utke² and Mats Tilset¹

Magnetic properties of [NpO₂(dpc)₂]^2- in solid and in solution

Julie Héron¹, Hélène Bolvin^2*

Simen P. Følkner, Raju Dey, Giovanni Occhipinti, Vidar R. Jensen, Erwan Le Roux

Daniel Ali, Hilde Lea Lein†, Karina Mathisen,

A. Chatzitakis,¹* X. Liu,¹ P. A. Carvalho,² M. Norderhaug Getz,¹ T. Norby¹

Frida Paulsen Danmo¹, Didrik R. Småbråten¹, Sandra H. Skjærvø^1,2,3, Sathya P. Singh¹, Kjell Wiik¹, Dennis Meier¹, and Sverre M. Selbach¹,*

Amir Masoud Dayaghi¹, Marit Stange², Christelle Denonville², Yngve Larring², Per Martin Rørvik², Truls Norby¹

Influence of ionic species and metal oxide - carbonate phase transformations on the ionic conduction behaviour of Gd-doped ceria - Li₂CO₃/Na₂CO₃composite membranes

Linn Katinka Emhjellen¹*, Tor S. Bjørheim¹, Marie-Laure Fontaine², Zuoan Li², Truls Norby¹

Point Defects in Monolayer MoS₂

Phosphites as precursors in thin film synthesis. Using LiPO₄ as cathode coating in Li-ion batteries.

X. Liu,¹* A. Chatzitakis,¹ P. A. Carvalho,² P. H. Backe,^3,4 M. Yang,^3,4, M. Bjørås,^3,4 T. Norby¹

Self-assembled Ni_0.98Li_0.02O and Zn_0.98Al_0.02O composite interface for thermoelectrics

Guro Sørli,Dragos Stoian†, Magnus Rønning§,Karina Mathisen

K. Xu,¹ E. Vøllestad,² Q. Ruan,³ J. Tang,³ A. Chatzitakis,¹* T. Norby¹

Pt_100-xRh_x/Al₂O₃ catalysts for ammonia oxidation at intermediate temperatures

P. Dhak^a, K. I. Skau^b, D. Waller^b, J. Skjelstad^c, H. Fjellvåg^a, A. O. Sjåstad^a

a Centre for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo, Norway
b Yara International ASA, Yara Technology Centre, P.O. Box 1130, N-3905 Porsgrunn, Norway
c K. A. Rasmussen, Strandvegen 165, 2316 Hamar, Norway

A. Chatzitakis^1*, S.C. Simonsen¹, M.L. Fontaine², M.S. Thomassen², I. Lorentzen³, T. Norby¹

1 Department of Chemistry, University of Oslo, SMN, FERMiO, Gaustadalléen 21, NO-0349 Oslo, Norway
2 SINTEF Industry, Forskningsveien 1, NO-0373 Oslo, Norway
3 NORECS AS, Gaustadalléen 21, NO-0349 Oslo, Norway

DFT study on proton uptake in BaFeO_3-x