Truls Norby

• Haugsrud, Reidar; Stange, Marit Synnøve Sæverud; Larring, Yngve; Strandbakke, Ragnar; Norby, Truls Eivind & Dayaghi, Amir Masoud (2021). Increasing the thermal expansion of proton conducting Y-doped BaZrO3 by Sr and Ce substitution. Solid State Ionics.  ISSN 0167-2738. . doi: 10.1016/j.ssi.2020.115534
• Kang, Xiaolan; Berberidou, Chrysanthi; Galeckas, Augustinas; Bazioti, Kalliopi; Sagstuen, Einar; Norby, Truls Eivind & Chatzitakis, Athanasios Eleftherios (2021). Visible Light Driven Photocatalytic Decolorization and Disinfection of Water Employing Reduced TiO2 Nanopowders. Catalysts.  ISSN 2073-4344.  11(2) . doi: 10.3390/catal11020228
• Mayandi, Jeyanthinath; Madathil, Reshma Krishnan; Abinaya, C; Bethke, Kevin; Venkatachalapathy, Vishnukanthan; Rademann, Klaus; Norby, Truls Eivind & Finstad, Terje (2021). Al-doped ZnO prepared by co-precipitation method and its thermoelectric characteristics. Materials Letters.  ISSN 0167-577X.  288 . doi: 10.1016/j.matlet.2021.129352 Show summary

  We report on structural and electrical characterization of zinc oxide material containing aluminum (Al:ZnO) prepared by a co-precipitation technique using different zinc and aluminum precursors. The as-prepared powders were calcinated and pre-annealed at 600 °C and 1200 °C. These were cold-pressed to pellets and sintered at 1000 °C. We also prepared ZnO material with no Al for comparisons. The electrical and thermal conductivity, as well as the Seebeck coefficient, were measured. These properties were correlated with structural analysis by X-ray diffraction characterization and scanning electron microscopy. The process yields a nanostructured material with much reduced thermal conductivity.

• Schuler, Raphael; Bianchini, Federico; Norby, Truls Eivind & Fjellvåg, Helmer (2021). Near-Broken-Gap Alignment between FeWO4 and Fe2WO6 for Ohmic Direct p–n Junction Thermoelectrics. ACS Applied Materials & Interfaces.  ISSN 1944-8244.  13(6), s 7416- 7422 . doi: 10.1021/acsami.0c19341
• Gunnæs, Anette Eleonora; Tofan, Raluca; Berland, Kristian; Gorantla, Sandeep Madhukar; Storaas, Thomas Aarflot; Desissa, Temesgen Debelo; Schrade, Matthias; Persson, Clas; Einarsrud, Mari-Ann; Wiik, Kjell; Norby, Truls Eivind & Kanas, Nikola (2020). Chemical stability of Ca3Co4−xO9+δ/CaMnO3−δ p–n junction for oxide-based thermoelectric generators. RSC Advances.  ISSN 2046-2069.  10(9), s 5026- 5031 . doi: 10.1039/c9ra07159h Full text in Research Archive. Show summary

  An all-oxide thermoelectric generator for high-temperature operation depends on a low electrical resistance of the direct p–n junction. Ca3Co4−xO9+δ and CaMnO3−δ exhibit p-type and n-type electronic conductivity, respectively, and the interface between these compounds is the material system investigated here. The effect of heat treatment (at 900 °C for 10 h in air) on the phase and element distribution within this p–n junction was characterized using advanced transmission electron microscopy combined with X-ray diffraction. The heat treatment resulted in counter diffusion of Ca, Mn and Co cations across the junction, and subsequent formation of a Ca3Co1+yMn1−yO6 interlayer, in addition to precipitation of Co-oxide, and accompanying diffusion and redistribution of Ca across the junction. The Co/Mn ratio in Ca3Co1+yMn1−yO6 varies and is close to 1 (y = 0) at the Ca3Co1+yMn1−yO6–CaMnO3−δ boundary. The existence of a wide homogeneity range of 0 ≤ y ≤ 1 for Ca3Co1+yMn1−yO6 is corroborated with density functional theory (DFT) calculations showing a small negative mixing energy in the whole range.

• Barakezehi, Marjan; Montazer, Majid; Sharif, Farhad; Norby, Truls Eivind & Chatzitakis, Athanasios Eleftherios (2020). MOF-modified polyester fabric coated with reduced graphene oxide/polypyrrole as electrode for flexible supercapacitors. Electrochimica Acta.  ISSN 0013-4686.  336, s 135743 . doi: 10.1016/j.electacta.2020.135743 Full text in Research Archive.
• Bondevik, Tarjei; Bjørheim, Tor Svendsen & Norby, Truls Eivind (2020). Assessing common approximations in space charge modelling to estimate the proton resistance across grain boundaries in Y-doped BaZrO3. Physical Chemistry, Chemical Physics - PCCP.  ISSN 1463-9076.  22(21), s 11891- 11902 . doi: 10.1039/c9cp06625j
• Bondevik, Tarjei; Polfus, Jonathan Marc & Norby, Truls Eivind (2020). Disagreements between space charge models and grain boundary impedance data in yttrium-substituted barium zirconate. Solid State Ionics.  ISSN 0167-2738.  353 . doi: 10.1016/j.ssi.2020.115369 Full text in Research Archive. Show summary

  Although the space charge model is commonly used to explain the high grain boundary resistance in proton conducting yttrium-substituted BaZrO3, it fails in its simplest forms with factors 10–40 to fit experimental data with respect to the characteristic frequency of the grain boundary impedance. We suggest modifications to the model, somewhat improving its fit. Including trapping effects of protons near yttrium substituents reduces the error only by factors less than 1.6. Increasing the width of the grain boundary core reduces the error with factors of 1.5–3. Discretizing the space charge layer, such that protons can only reside on specific, discrete sites, reduces the error with another factor of around 2. Considering reduced proton mobility in the GB by reducing its effective area may give a reduction in the fitting error of a factor of 2. Varying the dielectric constant in the GB does not affect the error considerably. Neither each single modification, nor their combined effect, can, however, account for the majority of the discrepancy between the space charge model and experimental data.

• Getz, Marit Norderhaug; Chatzitakis, Athanasios Eleftherios; Liu, Xin; Almeida Carvalho, Patricia; Bjørheim, Tor Svendsen & Norby, Truls Eivind (2020). Voids in walls of mesoporous TiO2 anatase nanotubes by controlled formation and annihilation of protonated titanium vacancies. Materials Chemistry and Physics.  ISSN 0254-0584.  239 . doi: 10.1016/j.matchemphys.2019.121953 Show summary

  Amorphous TiO2 nanotubes (TNTs) grown anodically on Ti metal in aqueous electrolytes show a crystallization behaviour strongly dependent on the atmosphere used during annealing at high temperature. In wet oxidizing conditions, the amorphous TNTs walls transform into relatively large and well crystallized anatase-like domains permeated by prismatic voids. On the other hand, crystallization of the amorphous nanotubes under dry reducing conditions induces nanocrystalline aggregates that do not show prismatic voids and exhibit different electronic properties. Supported by density functional theory calculations, it is argued that the formation or absence of voids can be understood in terms of formation and condensation of protonated titanium vacancies. Tunable morphology through defect chemical engineering as such, enables TNTs with increased surface area and catalytic activity, which find potential application in supercapacitors, sensors, photocatalysis, photoelectrochemistry, and dye-sensitized solar cells.

• Hisai, Yudai; Murakami, Kota; Kamite, Yukiko; Ma, Quanbao; Vøllestad, Einar; Manabe, Ryo; Matsuda, Takumi; Ogo, Shuhei; Norby, Truls Eivind & Sekine, Yasushi (2020). First observation of surface protonics on SrZrO3 perovskite under a H2 atmosphere. Chemical Communications.  ISSN 1359-7345.  56, s 2699- 2702 . doi: 10.1039/C9CC08757E Full text in Research Archive.
• Hu, Yang; Miikkulainen, Ville; Mizohata, Kenichiro; Norby, Truls Eivind; Nilsen, Ola & Fjellvåg, Helmer (2020). Ionic conductivity in LixTaOy thin films grown by Atomic Layer Deposition (ALD). Electrochimica Acta.  ISSN 0013-4686.  361 . doi: 10.1016/j.electacta.2020.137019 Full text in Research Archive.
• Kalland, Liv-Elisif Queseth; Løken, Andreas; Bjørheim, Tor Svendsen; Haugsrud, Reidar & Norby, Truls Eivind (2020). Structure, hydration, and proton conductivity in 50% La and Nd doped CeO2 – La2Ce2O7 and Nd2Ce2O7 – and their solid solutions. Solid State Ionics.  ISSN 0167-2738.  354 . doi: 10.1016/j.ssi.2020.115401
• Lysik, Aleksandra; Wejrzanowski, Tomasz; Cwieka, Karol; Skibinski, Jakub; Milewski, Jaroslaw; Marques, Fernando M.B.; Norby, Truls Eivind & Xing, Wen (2020). Silver coated cathode for molten carbonate fuel cells. International Journal of Hydrogen Energy.  ISSN 0360-3199.  45(38), s 19847- 19857 . doi: 10.1016/j.ijhydene.2020.05.112 Show summary

  Within this study, a layered cathode for use in a Molten Carbonate Fuel Cell (MCFC) has been developed. The substrate layer and reference MCFC cathode made of porous nickel was covered by a porous silver film with defined porosity and pore size. Both layers were fabricated using the tape casting method and further fired in a reductive atmosphere. The new cathode was assembled with other reference cell components to form a single MCFC, which was subjected to performance and durability tests. Scanning electron microscopy was used to analyze the microstructure of the materials before and after tests. The reference cathode was also studied for the comparison. The results show that the porous silver layer was able to enhance the electron transport between the cathode and current collector. It was also found that oxygen reduction is enhanced due to the presence of silver in the gas supply. As a result, the power density of the cell was increased by 50%. On the other hand, due to the separation from electrolyte by the NiO layer, no significant degradation of the silver layer, identified by SEM or electrochemical tests, was found after 1000 h.

• Michel, Kathrin; Bjørheim, Tor Svendsen; Norby, Truls Eivind; Janek, Jürgen & Elm, Matthias (2020). Importance of the spin-orbit interaction for a consistent theoretical description of small polarons in Pr-doped CeO2. Journal of Physical Chemistry C.  ISSN 1932-7447.  124(29), s 15831- 15838 . doi: 10.1021/acs.jpcc.0c05352
• Saeed, Sarmad Waheed; Norby, Truls & Bjørheim, Tor S. (2020). First-Principles Analyses of Nanoionic Effects at Oxide-Oxide Heterointerfaces for Electrochemical Applications. Journal of Physical Chemistry C.  ISSN 1932-7447.  124(26), s 14072- 14081 . doi: 10.1021/acs.jpcc.0c00385 Full text in Research Archive.
• Schuler, Raphael; Norby, Truls Eivind & Fjellvåg, Helmer (2020). Defects and polaronic electron transport in Fe2WO6. Physical Chemistry, Chemical Physics - PCCP.  ISSN 1463-9076.  22(27), s 15541- 15548 . doi: 10.1039/d0cp01588a Full text in Research Archive.
• Sun, Xinwei; Xu, Kaiqi; Chatzitakis, Athanasios Eleftherios & Norby, Truls Eivind (2020). Photocatalytic generation of gas phase reactive oxygen species from adsorbed water: Remote action and electrochemical detection. Journal of Environmental Chemical Engineering.  ISSN 2213-3437. . doi: 10.1016/j.jece.2020.104809 Full text in Research Archive. Show summary

  The improvement of indoor environments is of great importance as it can significantly improve human health, comfort and productivity. Herein, different forms of TiO2 nanorods were used as the photocatalyst for generation of reactive oxygen species (ROS) in a gas phase photoreactor under controlled humidity. Several parameters were investigated by monitoring the remote decolourisation of Methylene Blue (MB) embedded in a Nafion film. A decolourisation of 26% under 80% relative humidity was observed when the MB film was 0.5 cm away from the photocatalyst. The length and ratio of light/dark intervals have major impacts on the efficiency of the gas phase photocatalytic process, which we link to the amount of water adsorbed on the photocatalyst, as the source for hydroxyl radicals. Furthermore, the photocatalytic production of ROS was quantified through a polyaniline electrochemical sensor and a rate of 1 · 10*12 of ROS molecules s−1 was estimated. This study contributes to the efficacy of the gas phase photocatalytic method in air decontamination, for the development of efficient air cleaning devices.

• Szpunar, Iga; Strandbakke, Ragnar; Sørby, Magnus Helgerud; Wachowski, Sebastian Lech; Balaguer, Maria; Tarach, Mateusz; Serra, José M.; Witkowska, Agnieszka; Dzik, Ewa; Norby, Truls Eivind; Gazda, Maria & Mielewczyk-Gryń, Aleksandra (2020). High-temperature structural and electrical properties of BaLnCo2O6 positrodes. Materials.  ISSN 1996-1944.  13(18), s 1- 18 . doi: 10.3390/ma13184044 Full text in Research Archive.
• Takahashi, Ayako; Inagaki, Reona; Torimoto, Maki; Hisai, Yudai; Matsuda, Taku; Ma, Quanbao; Seo, Jeong Gil; Higo, Takuma; Tsuneki, Hideaki; Ogo, Shuhei; Norby, Truls Eivind & Sekine, Yasushi (2020). Effects of metal cation doping in CeO2 support on catalytic methane steam reforming at low temperature in an electric field. RSC Advances.  ISSN 2046-2069.  10, s 14487- 14492 . doi: 10.1039/d0ra01721c Full text in Research Archive.
• Torimoto, Maki; Ogo, Shuhei; Hisai, Yudai; Takahashi, Ayako; Ma, Quanbao; Seo, Jeong Gil; Tsuneki, Hideaki; Norby, Truls Eivind & Sekine, Yasushi (2020). Support effects on catalysis of low temperature methane steam reforming. RSC Advances.  ISSN 2046-2069.  10, s 26418- 26424 . doi: 10.1039/d0ra04717a Full text in Research Archive.
• Wachowski, Sebastian Lech; Szpunar, Iga; Sørby, Magnus Helgerud; Mielewczyk-Gryń, Aleksandra; Balaguer, Maria; Ghica, Corneliu; Istrate, Marian Cosmin; Gazda, Maria; Gunnæs, Anette Eleonora; Serra, José M.; Norby, Truls Eivind & Strandbakke, Ragnar (2020). Structure and water uptake in BaLnCo2O6−δ (Ln = La, Pr, Nd, Sm, Gd, Tb and Dy). Acta Materialia.  ISSN 1359-6454.  199, s 297- 310 . doi: 10.1016/j.actamat.2020.08.018 Full text in Research Archive.
• Xu, Kaiqi; Chatzitakis, Athanasios Eleftherios; Risbakk, Sanne; Yang, Mingyi; Backe, Paul Hoff; Grandcolas, Mathieu; Bjørås, Magnar & Norby, Truls Eivind (2020). High performance and toxicity assessment of Ta3N5 nanotubes for photoelectrochemical water splitting. Catalysis Today.  ISSN 0920-5861. . doi: 10.1016/j.cattod.2019.12.031 Full text in Research Archive. Show summary

  In this work, Co-based cocatalysts are electrodeposited on mesoporous Ta3N5 nanotubes. The electrodeposition time is varied and the optimized photoelectrode reaches a photocurrent density of 6.3 mA/cm2 at 1.23 V vs. SHE, under simulated solar illumination of 1 Sun, in 1 M NaOH. The best performing electrode, apart from the high photocurrent density, shows improved stability under intense photoelectrochemical water splitting conditions. The dual function of the cocatalyst to improve not only the photoelectrochemical performance, but also the stability, is highlighted. Moreover, we adopted a simple protocol to assess the toxicity of Co and Ta contained nanostructured materials (representing used photoelectrodes) employing the human cell line HeLa S3 as target cells.

• Singh, Sathya Prakash; Kanas, Nikola; Desissa, Temesgen Debelo; Einarsrud, Mari-Ann; Norby, Truls Eivind & Wiik, Kjell (2019). Thermoelectric properties of non-stoichiometric CaMnO3-d composites formed by redox-activated exsolution.. Journal of the European Ceramic Society.  ISSN 0955-2219.  40(4), s 1344- 1351 . doi: 10.1016/j.jeurceramsoc.2019.11.027 Full text in Research Archive.
• Singh, Sathya Prakash; Kanas, Nikola; Desissa, Temesgen Debelo; Johnsson, Mats; Einarsrud, Mari-Ann; Norby, Truls Eivind & Wiik, Kjell (2019). Thermoelectric properties of A-site deficient La-doped SrTiO3 at 100–900 °C under reducing conditions. Journal of the European Ceramic Society.  ISSN 0955-2219.  40(2), s 401- 407 . doi: 10.1016/j.jeurceramsoc.2019.09.024 Full text in Research Archive.
• Barakezehi, Marjan; Montazer, Majid; Sharif, Farhad; Norby, Truls Eivind & Chatzitakis, Athanasios Eleftherios (2019). A textile-based wearable supercapacitor using reduced graphene oxide/polypyrrole composite. Electrochimica Acta.  ISSN 0013-4686.  305, s 187- 196 . doi: 10.1016/j.electacta.2019.03.058
• Bondevik, Tarjei; Ness, Heine Håland; Bazioti, Kalliopi; Norby, Truls Eivind; Løvvik, Ole Martin; Koch, Christoph T. & Prytz, Øystein (2019). Investigation of the electrostatic potential of a grain boundary in Y-substituted BaZrO3 using inline electron holography. Physical Chemistry, Chemical Physics - PCCP.  ISSN 1463-9076.  21(32), s 17662- 17672 . doi: 10.1039/c9cp02676b Full text in Research Archive. Show summary

  We apply inline electron holography to investigate the electrostatic potential across an individual BaZr0.9Y0.1O3 grain boundary. With holography, we measure a grain boundary potential of −1.3 V. Electron energy loss spectroscopy analyses indicate that barium vacancies at the grain boundary are the main contributors to the potential well in this sample. Furthermore, geometric phase analysis and density functional theory calculations suggest that reduced atomic density at the grain boundary also contributes to the experimentally measured potential well.

• Grandcolas, Mathieu; Wabende, Brian; Yang, Juan; Mei, Sen; Xu, Kaiqi; Norby, Truls Eivind & Chatzitakis, Athanasios Eleftherios (2019). Preparation of TiO2 rutile nanorods decorated with cobalt oxide nanoparticles for solar photoelectrochemical activity. Materials Letters.  ISSN 0167-577X.  247, s 1- 3 . doi: 10.1016/j.matlet.2019.03.087 Show summary

  The present paper investigates the preparation of titanium dioxide (TiO2) nanorods decorated with cobalt oxide (Co3O4) nanoparticles and its application as solar photoelectrocatalyst. TiO2 rutile nanorods have been prepared on conductive glass via a hydrothermal reaction in acidic media, shaped as squared rods with an average length of 1.7 µm and thicknesses between 50 and 120 nm. Co3O4 nanoparticles with an average diameter of 30 nm were synthesized using a simple precipitation method. Spin coating the nanoparticles on the TiO2 nanorods shows enhanced photocurrents under simulated solar light up to 1.3 mA/cm2 at 1.6 V vs. SHE.

• Han, Feng; Zhou, Xingping; Dayaghi, Amir Masoud; Norby, Truls Eivind; Stange, Marit Synnøve Sæverud; Sata, Noriko & Costa, Remi (2019). Development of Metal Supported Cells Using BaZrO3-Based Proton Conducting Ceramics. ECS Transactions.  ISSN 1938-5862.  91(1), s 1035- 1045 . doi: 10.1149/09101.1035ecst
• Kanas, Nikola; Singh, Sathya Prakash; Rotan, Magnus; Desissa, Temesgen Debelo; Grande, Tor; Wiik, Kjell; Norby, Truls Eivind & Einarsrud, Mari-Ann (2019). Thermoelectric Properties of Ca3Co2−xMnxO6 (x = 0.05, 0.2, 0.5, 0.75, and 1). Materials.  ISSN 1996-1944.  12(3) . doi: 10.3390/ma12030497 Full text in Research Archive. Show summary

  High-temperature instability of the Ca3Co4−yO9+δ and CaMnO3−δ direct p-n junction causing the formation of Ca3Co2−xMnxO6 has motivated the investigation of the thermoelectric performance of this intermediate phase. Here, the thermoelectric properties comprising Seebeck coefficient, electrical conductivity, and thermal conductivity of Ca3Co2−xMnxO6 with x = 0.05, 0.2, 0.5, 0.75, and 1 are reported. Powders of the materials were synthesized by the solid-state method, followed by conventional sintering. The material Ca3CoMnO6 (x = 1) demonstrated a large positive Seebeck coefficient of 668 μV/K at 900 °C, but very low electrical conductivity. Materials with compositions with x < 1 had lower Seebeck coefficients and higher electrical conductivity, consistent with small polaron hopping with an activation energy for mobility of 44 ± 6 kJ/mol and where both the concentration and mobility of hole charge carriers were proportional to 1−x. The conductivity reached about 11 S·cm−1 at 900 °C for x = 0.05. The material Ca3Co1.8Mn0.2O6 (x = 0.2) yielded a maximum zT of 0.021 at 900 °C. While this value in itself is not high, the thermodynamic stability and self-assembly of Ca3Co2−xMnxO6 layers between Ca3Co4−yO9+δ and CaMnO3−δ open for new geometries and designs of oxide-based thermoelectric generators.

• Liu, Xin; Almeida Carvalho, Patricia; Getz, Marit Norderhaug; Norby, Truls Eivind & Chatzitakis, Athanasios Eleftherios (2019). Black Anatase TiO2 Nanotubes with Tunable Orientation for High Performance Supercapacitors. Journal of Physical Chemistry C.  ISSN 1932-7447.  126(36), s 21391- 21940 . doi: 10.1021/acs.jpcc.9b05070 Show summary

  Black TiO2 is a versatile material that finds many applications in the field of photocatalysis but also in energy storage devices, such as supercapacitors. In this work, a new method is developed for the synthesis of black TiO2 in the form of nanotubes. Amorphous TiO2 nanotubes (TNTs) are annealed and reduced in the presence of CaH2, and by a simple manipulation, we are able to obtain control over the preferred crystal orientation. The reduced TNTs show high power and energy densities, as well as unprecedented stability under intensive charge/discharge cycling. The oriented reduced TNTs show metallic-like behavior with improved conductivity when compared to the polycrystalline analogue. This work contributes to the development of highly robust and efficient oxides for electrode material in supercapacitors.

• Liu, Xin; Bjørheim, Tor Svendsen; Vines, Lasse; Fjellvåg, Øystein; Granerød, Cecilie Skjold; Prytz, Øystein; Yamamoto, Takafumi; Kageyama, Hiroshi; Norby, Truls Eivind & Haugsrud, Reidar (2019). Highly Correlated Hydride Ion Tracer Diffusion in SrTiO3–xHx Oxyhydrides. Journal of the American Chemical Society.  ISSN 0002-7863.  141(11), s 4653- 4659 . doi: 10.1021/jacs.8b12985 Full text in Research Archive.
• Morland, Bjørn Helge; Norby, Truls Eivind; Tjelta, Morten & Svenningsen, Gaute (2019). Effect of SO2, O2, NO2, and H2O Concentrations on Chemical Reactions and Corrosion of Carbon Steel in Dense Phase CO2. Corrosion.  ISSN 0010-9312.  75(11), s 1327- 1338 . doi: 10.5006/3111 Full text in Research Archive.
• Morland, Bjørn Helge; Tjelta, Morten; Norby, Truls Eivind & Svenningsen, Gaute (2019). Acid reactions in hub systems consisting of separate non-reactive CO2 transport lines. International Journal of Greenhouse Gas Control.  ISSN 1750-5836.  87, s 246- 255 . doi: 10.1016/j.ijggc.2019.05.017 Full text in Research Archive.
• Norby, Truls Eivind; Jensen, Emil Høj & Sartori, Sabrina (2019). Deep decarbonization efforts in Norway for energy sustainability. MRS Energy & Sustainability.  ISSN 2329-2229.  6 . doi: 10.1557/mre.2019.12
• Saeed, Sarmad Waheed; Norby, Truls Eivind & Bjørheim, Tor Svendsen (2019). Charge-Carrier Enrichment at BaZrO3/SrTiO3 Interfaces. Journal of Physical Chemistry C.  ISSN 1932-7447.  123(34), s 20808- 20816 . doi: 10.1021/acs.jpcc.9b06296
• Sazinas, Rokas; Sunding, Martin Fleissner; Thøgersen, Annett; Sakaguchi, Isao; Norby, Truls Eivind; Grande, Tor & Polfus, Jonathan M. (2019). Surface reactivity and cation non-stoichiometry in BaZr1-xYxO3-δ (x=0-0.2) exposed to CO2 at elevated temperature. Journal of Materials Chemistry A.  ISSN 2050-7488.  7(8), s 3848- 3856 . doi: 10.1039/c8ta11021b Full text in Research Archive.
• Stange, Marit Synnøve Sæverud; Dayaghi, Amir Masoud; Denonville, Christelle; Larring, Yngve; Rørvik, Per Martin; Haugsrud, Reidar & Norby, Truls Eivind (2019). Fabrication of metal-supported proton-conducting electrolysers with thin film Sr- And Ce-doped BZY electrolyte. ECS Transactions.  ISSN 1938-5862.  91(1), s 941- 949 . doi: 10.1149/09101.0941ecst Show summary

  n this work, we present fabrication and initial testing of metal-supported proton ceramic electrolyser (MS-PCEC) single cells with a thin electrolyte. Plansee ITM porous metal is used as metal support. Spray-coating is used to deposit a conducting layer of La1-xSrxTi1-yNiyO3-δ (LSTN) which is used for low temperature (600-800 °C) deposition of a gas-tight, thin-film layer (~2 μm) of electrolyte by pulsed laser deposition (PLD). Post-annealing of the electrolyte is evaluated to improve its performance. In order to have a smaller thermal expansion coefficient (TEC) mismatch towards LSTN (~10-11 × 10-6 K-1), we developed a new Sr- and Ce-doped proton-conducting electrolyte, yielding a larger TEC (~10-11 × 10-6 K-1) compared to BZY (~8 × 10-6 K-1). The cell with Pt as air electrode shows acceptable open circuit voltage and low overpotentials at 600 °C, demonstrating the potential of developing the first working MS-PCEC.

• Sun, Xinwei; Simonsen, Stian Christopher; Norby, Truls Eivind & Chatzitakis, Athanasios Eleftherios (2019). Composite Membranes for High Temperature PEM Fuel Cells and Electrolysers: A Critical Review. Membranes.  ISSN 2077-0375.  9(7) . doi: 10.3390/membranes9070083
• Vøllestad, Einar; Strandbakke, Ragnar; Tarach, Mateusz; Catalán-Martinez, David; Fontaine, Marie-Laure; Beeaff, Dustin; Clark, Daniel Ryan; Serra, José M. & Norby, Truls Eivind (2019). Mixed proton and electron conducting double perovskite anodes for stable and efficient tubular proton ceramic electrolysers. Nature Materials.  ISSN 1476-1122.  18(7), s 752- 759 . doi: 10.1038/s41563-019-0388-2 Full text in Research Archive. Show summary

  Hydrogen production from water electrolysis is a key enabling energy storage technology for the large-scale deployment of intermittent renewable energy sources. Proton ceramic electrolysers (PCEs) can produce dry pressurized hydrogen directly from steam, avoiding major parts of cost-driving downstream separation and compression. However, the development of PCEs has suffered from limited electrical efficiency due to electronic leakage and poor electrode kinetics. Here, we present the first fully operational BaZrO3-based tubular PCE, with 10 cm2 active area and a hydrogen production rate above 15 Nml min−1. The novel steam anode Ba1−xGd0.8La0.2+xCo2O6−δ exhibits mixed p-type electronic and protonic conduction and low activation energy for water splitting, enabling total polarization resistances below 1 Ω cm2 at 600 °C and Faradaic efficiencies close to 100% at high steam pressures. These tubular PCEs are mechanically robust, tolerate high pressures, allow improved process integration and offer scale-up modularity.

• Xing, Wen; Li, Zuoan; Peters, Thijs; Fontaine, Marie-Laure; McCann, Michael; Evans, Anna; Norby, Truls Eivind & Bredesen, Rune (2019). Improved CO2 flux by dissolution of oxide ions into the molten carbonate phase of dual-phase CO2 separation membranes. Separation and Purification Technology.  ISSN 1383-5866.  212, s 723- 727 . doi: 10.1016/j.seppur.2018.11.090 Full text in Research Archive.
• Xu, Kaiqi; Chatzitakis, Athanasios Eleftherios; Jensen, Ingvild Julie Thue; Grandcolas, Mathieu & Norby, Truls Eivind (2019). Ta3N5/Co(OH)x composites as photocatalysts for photoelectrochemical water splitting. Photochemical and Photobiological Sciences.  ISSN 1474-905X.  18(4), s 837- 844 . doi: 10.1039/c8pp00312b Full text in Research Archive.
• Xu, Kaiqi; Chatzitakis, Athanasios Eleftherios; Vøllestad, Einar; Ruan, Qiushi; Tang, Junwang & Norby, Truls Eivind (2019). Hydrogen from wet air and sunlight in a tandem photoelectrochemical cell. International Journal of Hydrogen Energy.  ISSN 0360-3199.  44(2), s 587- 593 . doi: 10.1016/j.ijhydene.2018.11.030 Full text in Research Archive.

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• Kalland, Liv-Elisif Queseth; Norby, Truls Eivind; Mohn, Chris Erik & Haugsrud, Reidar (2021). Ab-initio modelling and experimental study of order-disorder, hydration, and ionic conductivity of fluorite-related oxides. Series of dissertations submitted to the Faculty of Mathematics and Natural Sciences, University of Oslo.. 2348. Show summary

  Hydrogen will play a key role in a zero-emission society, and proton (H+) conducting oxides have gained interest as solid-state electrolytes for next-generation electrochemical devices for fuel cells and electrolyzers. Understanding the effect of structure on materials functional properties is important for enhancing the performance of such electrolytes. Oxides with fluorite related crystal structures are interesting for their high oxide ion and proton (H+) conductivities, and in this work the relationship between the atomic structure and the materials properties such as ionic conductivity and hydration properties have been studied for three different oxides. They are oxygen deficient with respect to the fluorite structure and the vacant oxide ion sites can thus be ordered or disordered. Through a combination of different experimental and computational methods the nature and degree of ordering and the atomic structure have been determined, and correlated to the properties of the cations present, such as size and electronegativity. The work further focuses on whether ordering the oxide ion vacancies affects the hydration and consequently the proton conductivity. The results have led us to propose a new model for hydration of heavily doped yet disordered fluorite oxides.

• Norby, Truls Eivind (2021). Fra forsker til grunder: Hvilken hjelp skulle jeg ønsket meg.
• Schuler, Raphael; Fjellvåg, Helmer & Norby, Truls Eivind (2021). Oxide thermoelectrics - materials, junctions and modules. Series of dissertations submitted to the Faculty of Mathematics and Natural Sciences, University of Oslo.. 2364. Show summary

  Thermoelectric materials are able to directly convert heat into electricity, which makes them predestined candidates for the recuperation of waste heat and contributing to a more efficient energy economy. They hold enormous potential for energy generation, since all thermodynamic processes lose a major portion of their energy in the form of waste heat. However, conventional thermoelectric materials are often toxic, scarce and/or expensive, and show limited high temperature stability, which currently limits their relevance for large-scale applications. Recently, oxide thermoelectric materials, composed of abundant elements have attracted increased interest, as they offer a cheaper, environmental-friendly, and high-temperature stable alternative. They are usually discovered and researched individually, and only later combined to a p-n pair in a module, which often leads to complications, like thermal mismatch or reactions. In this work the approach was taken to design a compatible pair of new thermoelectric oxides that preclude complications in advance. This novel approach is demonstrated on a model pair of iron tungstates, which show promising thermoelectric properties and an exceptional band alignment, which could prove to be key properties for future thermoelectrics.

• Andersen, Håkon; Norby, Truls Eivind & Strandbakke, Ragnar (2020). Functional Properties and Electrochemical Performance of New Positrode Materials for Proton Ceramic Electrochemical Cells. Show summary

  Proton Ceramic Electrochemical Cells (PCECs) exhibit high efficiency at lower temperatures due to the low activation energy ofproton transport. PCECs havealso obtained a great interest for its fuel utilisation, which result in a higher operating cell voltage and efficiency. However, the development of efficient commercial PCECs has been held back by the lack ofanefficient electrode at the oxygen steam side, also known as positrode.BaGd0.8La0.2Co2O6-δ (BGLC82) has shown to be a state of the art positrode, with Mixed Proton and Electronic Conductivity (MPEC). By using BGLC82 as a backbone in developing new and efficient electrode materials, the primary object of this thesis is to study the functional properties of selected doped BGLC82 materials, with their focus as positrodematerials for PCECs. BGLC82 was 10 % doped with the chosen materials zinc, titanium and zirconia (BaGd0.8La0.2Co1.8X0.2O6-δX=Zn, Ti, Zr). The BGLC82 compositionswere synthesised by solid-state reaction (SSR). BGLC82 Ti and Zn showed to obtain single phases, whereasBGLC82: Zr exhibit a secondary phase of BaZrO3. To try to obtain a single phase of BGLC82: Zr sol-gel (SG) synthesis was used. BGLC82: Zr still exhibited the same secondary phase obtained for SSR, but with a lower amount. This implies that the solubility of Zr in BGLC82 was exceeded.BGLC82 Ti and Zn were tested for proton uptake by Thermogravimetric Analysis (TGA)at 300 –500 °C. The measurementsshowed that BGLC82: Ti exhibitsa higher proton uptake than BGLC82, whereas BGLC82: Zn obtain lower proton uptake than BGLC82. This implies that the donor dopant stabilises the protonic defectsin the BGLC82 structure, dueto the basisety of the cation. For the experimental setup, small pellets of the BGLC82 composites were placed on top of a BaZr0.7Ce0.2Y0.1O3-δ(BZCY72) at the same time and held in place by a spring load. To obtain the best contact between the electrodes and the electrolyte, the surfaces in contact were polished. Platinumwas used as counter and reference electrode,placed on the opposite side of the BGLC82 composite electrodes.

• Andersen, Karoline Sjøen; Norby, Truls Eivind & Chatzitakis, Athanasios Eleftherios (2020). Hydrophobic coatings for offshore PV modules: Impact of precipitation from seawater on the protective glass.
• Andreassen, Magnus Haga; Norby, Truls Eivind & Chatzitakis, Athanasios Eleftherios (2020). Synthesis, characterization, and optimization of Cu2O photocathodes for solid-state photoelectrochemical cells.
• James, Roystan; Norby, Truls Eivind; Vines, Lasse & Bjørheim, Tor Svendsen (2020). Electrical properties of La2CuO4 and Nd2CuO4 and their coexistent p-n heterojunction.
• Liu, Xin; Risbakk, Sanne; Almeida Carvalho, Patricia; Yang, Mingyi; Backe, Paul Hoff; Bjorås, Magnar; Norby, Truls Eivind & Chatzitakis, Athanasios Eleftherios (2020). Hydrogenase-assisted catalysis on titania electrode oxides. Show summary

  The widespread use of fuel cells and water splitting devices for energy generation and storage is limited by the dependence on noble metal catalysts. There is thus a tremendous need for the development of efficient electrocatalysts based on Earth-abundant elements. Nature inspired hydrogenases (HydA) are metallo-enzymes that catalyze the reversible reaction of H2 to protons and electrons. Hydrogenases containing Fe at the active sites, known as [FeFe]-HydA, show activities comparable to that of Pt. This work addresses a new class of electrodes for [FeFe]-HydA attachment and bio-assisted catalysis based on TiO2 nanotubes. The conducting oxide material provides suitable electronic conduction and hydrophilicity, while the nanostructure ensures tunability (tube length, crystal orientation and pore diameter) and high surface area for HydA attachment. In this work, electron microscopy is used to characterize the bio-electrodes. Based on the experimental findings, density functional theory (DFT) calculations are used to probe the catalytic reaction sites on the HydA and address the interaction between enzymes and TiO2. 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.

• Morland, Bjørn Helge; Svenningsen, Gaute & Norby, Truls Eivind (2020). Corrosion in CO2 transport pipeline. Formation of corrosive phases in dense phase CO2. Series of dissertations submitted to the Faculty of Mathematics and Natural Sciences, University of Oslo.. 2215. Show summary

  Carbon capture and storage is suggested as one of the solutions to reduce CO2 emissions. Material choice is an important part for the total cost of the transport system for CO2. The present work comprises investigations of corrosive situations which could occur during transport of CO2 for injection to reservoirs. As CO2 with various combinations and concentrations of impurities were tested in a systematic manner, it was clear that combinations from established CO2 transport recommendations resulted in formation of a separate aqueous phase that contained high concentrations of sulfuric and nitric acid. However, many new impurity combinations were basically inert and could be considered safe to transport in carbon steel pipelines. Altogether, the present work has identified many important aspects of corrosion and chemical reactions for CO2 transport. This results in a better understanding of the processes that leads to corrosion and is needed for the making of a CO2 specification which ensure the integrity of pipelines or ships.

• Norby, Truls Eivind (2020). Ceramic proton conductors and photoelectrochemistry for hydrogen.
• Norby, Truls Eivind (2020). Ceramic proton conductors for natural gas, hydrogen, and ammonia.
• Norby, Truls Eivind (2020). Ceramic proton conductors for natural gas, hydrogen, and ammonia.
• Norby, Truls Eivind (2020). Electrodics for Protonics.
• Norby, Truls Eivind (2020). Electrodics for Protonics.
• Norby, Truls Eivind (2020). Space Charge Effects at Interfaces of Proton Conducting Oxides.
• Norby, Truls Eivind & Sun, Xinwei (2020). Protonic conduction in water and hydrogen adsorbed in porous materials.
• Olofsson, Andreas Connor & Norby, Truls Eivind (2020). An investigation of Ca3CoMnO6 as a thin-film layer on oxide thermoelectric materials.
• Ormann, Brage Otto; Norby, Truls Eivind & Vines, Lasse (2020). Stable oxide p-n heterojunctions -- NiO-ZnO based transistor.
• Simonsen, Stian Christopher; Norby, Truls Eivind & Chatzitakis, Athanasios Eleftherios (2020). Nafion®-Ceramic Composite Electrolytes for Proton Exchange Membrane Fuel Cells at Elevated Temperatures.
• Strandbakke, Ragnar; Bjørheim, Tor Svendsen; Sørby, Magnus Helgerud; Szpunar, Iga; Wachowski, Sebastian Lech; Mielewczyk-Gryń, Aleksandra; Balaguer, María; Almeida Carvalho, Patricia; Serra, José M. & Norby, Truls Eivind (2020). Governing principles of hydration in mixed conducting oxides.
• Thøgersen, Annett; Diplas, Spyridon; Michel, Kathrin; Bjørheim, Tor Svendsen; Prytz, Øystein & Norby, Truls Eivind (2020). The surface of CeO2 unravelled.
• Xu, Kaiqi; Chatzitakis, Athanasios Eleftherios; Backe, Paul Hoff; Ruan, Qiushi; Tang, Junwang; Bjørås, Magnar; Rise, Frode & Norby, Truls Eivind (2020). The use of NMR to assess the activity of formate dehydrogenase biocatalysts for CO2 utilization.
• Xu, Kaiqi; Norby, Truls Eivind; Chatzitakis, Athanasios Eleftherios & Bjørheim, Tor Svendsen (2020). Artificial photosynthesis – Advanced nanomaterials and use of biocatalysts for novel photoelectrochemical cells. Series of dissertations submitted to the Faculty of Mathematics and Natural Sciences, University of Oslo.. 2254. Show summary

  The capture and storage of solar energy in chemical form by a photoelectrochemical (PEC) cell is an elegant and simple solution to the increasing energy demands and needs for chemicals and fuels from non-fossil sources. We first developed a facile fabrication method of a monolithic solid-state PEC (SSPEC) cell, which utilizes a solid-state polymer electrolyte and minimizes the distance between the two electrodes. The recent progress in understanding of surface proton conduction in porous ceramic-based electrolytes led to the idea of using the SSPEC cell for hydrogen production through water vapor splitting. The traditionally Pt-based cathode was replaced by an earth-abundant photocathode, g-C3N4, which increased the intrinsic photo-induced electrical field by a factor of three. Such a monolithic SSPEC cell working fully in the gas phase was demonstrated first time, and can play an important role for clean energy production in rural or other areas where grid infrastructure and clean water sources are limited or absent. CO2 utilization is considered a key player in a carbon-free energy economy, emphasising the importance of CO2 capture and conversion. We have successfully demonstrated how a bio-catalyst (enzyme) can be coupled with traditional chemical engineering for this purpose. To approach this, a stable, highly photo-active material - Ta3N5 nanotubes - has been synthesized and tested in a photoelectrochemical cell. It reaches close to its theoretical performance in photo-assisted water splitting. We then coupled the Ta3N5 nanotubes as the photoabsorber together with an optimised enzyme - formate dehydrogenase (FDH) - in a photoelectrochemical cell. The aim is to mimic natural photosynthesis to reduce CO2 into a valuable chemical form – formic acid. A solar-driven reduction of CO2 and water to formic acid at close to 100% faradaic efficiency has been reached.

• Bondevik, Tarjei; Prytz, Øystein & Norby, Truls Eivind (2019). Investigation of the electrostatic potential of a grain boundary in Y-substituted BaZrO3 using inline electron holography.
• Both, Kevin Gregor; Norby, Truls Eivind; Bjørheim, Tor Svendsen & Løvvik, Ole Martin (2019). Cu2O – ZnO p-n Junctions: Thermodynamics, Structure, and Properties – an Experimental and Theoretical Study.
• Dayaghi, Amir Masoud; Stange, Marit Synnøve Sæverud; Denonville, Christelle; Larring, Yngve; Rørvik, Per Martin; Haugsrud, Reidar & Norby, Truls Eivind (2019). Thin-film electrolyte with TEC optimized for metal-supported proton ceramic electrochemical cell.
• Frøen, Emil Herman; Norby, Truls Eivind; Bjørheim, Tor Svendsen & Løvvik, Ole Martin (2019). Coexistent Oxide p-n Junctions: DFT Analysis of Interfaces Between Nickel Oxide and Zinc Oxide.
• Kolding, Jonas; Norby, Truls Eivind; Sartori, Sabrina & Larring, Yngve (2019). Conductivity and Defects in Al-doped Li7La3Zr2O12 - A solid-state Li-ion conductor.
• Liu, Xin; Chatzitakis, Athanasios Eleftherios; Almeida Carvalho, Patricia; Risbakk, Sanne; Yang, Mingyi; Backe, Paul Hoff & Norby, Truls Eivind (2019). Enzyme-assisted Catalysis on Titania Electrodes.
• Norby, Truls Eivind (2019). Electrodics for proton ceramic electrochemical cells - positrodes.
• Norby, Truls Eivind (2019). Electrodics for protonics.
• Norby, Truls Eivind (2019). Ions and electrons at interfaces of functional ionic materials.
• Norby, Truls Eivind (2019). Novel aspects of electrocatalysis for hydrogen.
• Norby, Truls Eivind (2019). Proton ceramic electrochemical cells for efficient hydrogen production.
• Norby, Truls Eivind (2019). Role of surface protonics for electrodics.
• Norby, Truls Eivind (2019). Water and protonic conduction on surfaces of nanomaterials - role in catalytic processes. Show summary

  Water vapour chemisorbs on surfaces as protons and hydroxide ions at elevated temperatures and physisorbs as molecular water at lower temperatures in ice-like thin and liquid-like thick layers, respectively. Also hydrogen adsorbs and dissociates. All adsorbates give rise to surface protonic conduction of different mechanisms and magnitude depending on temperature and acidity of the surface. The surface protonic conduction may be used in electrolytes for electrochemical cells, but in this talk focus is more on its effect in some catalytic processes in finely porous nanomaterials.

• Norby, Truls Eivind & Kalland, Liv-Elisif Queseth (2019). Protons in heavily doped CeO2 and related compounds.
• Norby, Truls Eivind; Kalland, Liv-Elisif Queseth; Løken, Andreas; Bjørheim, Tor Svendsen & Haugsrud, Reidar (2019). Hydration of fluorite-related rare-earth cerates.
• Norby, Truls Eivind; Liu, Xin; Bjørheim, Tor Svendsen & Haugsrud, Reidar (2019). Hydride ion conduction.
• Norby, Truls Eivind & Sun, Xinwei (2019). Hydrogen and clean air - Norway and China.
• Norby, Truls Eivind & Sun, Xinwei (2019). Novel UiO Technologies for Green Energy and Clean Air in China.
• Pedersen, Madeeha Khalid & Norby, Truls Eivind (2019). Kröger-Vink compatible notation for defect chemistry and transport in Li-ion conducting disordered garnet-type oxides.
• Pedersen, Madeeha Khalid; Norby, Truls Eivind & Strandbakke, Ragnar (2019). Fundamentals of Positrodes for Proton Ceramic Electrochemical Cells.
• sata, noriko; han, feng; costa, remi; Zhou, Xingping; Stange, Marit Synnøve Sæverud; Dayaghi, Amir Masoud & Norby, Truls Eivind (2019). Development of Metal Supported Cells Using BaZrO3-Based Proton Conducting Ceramics.
• Stange, Marit Synnøve Sæverud; Dayaghi, Amir Masoud; Denonville, Christelle; Larring, Yngve; Rørvik, Per Martin; Haugsrud, Reidar & Norby, Truls Eivind (2019). Fabrication of Metal-Supported Proton-Conducting Electrolysers with Thin Film Sr- and Ce-Doped BZY Electrolyte.
• Stange, Marit Synnøve Sæverud; Dayaghi, Amir Masoud; Denonville, Christelle; Larring, Yngve; Rørvik, Per Martin; Haugsrud, Reidar & Norby, Truls Eivind (2019). Key challenges in fabrication of metal-supported thin film proton conducting electrolyser cells.
• Strandbakke, Ragnar; Balaguer, Maria; Wachowski, Sebastian Lech; Mielewczyk-Gryn, Aleksandra; Almeida Carvalho, Patricia; Sørby, Magnus Helgerud & Norby, Truls Eivind (2019). Protonics, stability and electrochemistry of Ba1‑xGd1-yLax+yCo2O6-δ (BGLC).
• Strandbakke, Ragnar; Bjørheim, Tor Svendsen; Sørby, Magnus Helgerud; Szpunar, Iga; Wachowski, Sebastian Lech; Mielewczyk-Gryn, Aleksandra; Balaguer, Maria; Almeida Carvalho, Patricia & Norby, Truls Eivind (2019). Protons in mixed conducting Ba1‑xGd1‑yLax+yCo2O6‑δ (BGLC).
• Strandbakke, Ragnar; Bjørheim, Tor Svendsen; Sørby, Magnus Helgerud; Wachowski, Sebastian Lech; Mielewczyk-Gryn, Aleksandra; Balaguer, Maria; Gunnæs, Anette Eleonora; Almeida Carvalho, Patricia & Norby, Truls Eivind (2019). Hydration and hydrogenation of mixed conducting BaGd1‑xLaxCo2O6‑δ (BGLC).
• Strandbakke, Ragnar; Bjørheim, Tor Svendsen; Vøllestad, Einar; Mielewczyk-Gryn, Aleksandra; Wachowski, Sebastian Lech; Lewandowska, Iga; Balaguer, Maria; Sørby, Magnus Helgerud & Norby, Truls Eivind (2019). Defect chemistry of mixed conducting double perovskites.
• Strandbakke, Ragnar; Vøllestad, Einar; Sørby, Magnus Helgerud & Norby, Truls Eivind (2019). Defect chemistry of mixed conducting double perovskites.
• Sun, Xinwei; Chatzitakis, Athanasios Eleftherios & Norby, Truls Eivind (2019). Composite membranes for high temperature PEM fuel cells and electrolysers. Show summary

  Polymer electrolyte membrane(PEM) fuel cells and electrolysers offer efficient use and production of H2 for emission-free transport and sustainable energy systems. In order to reduce the cost,complexity,flooding,catalyst poisoning and degradation,operation above 80°C and at lower relative humidities(RH) is preferable. Acid doped polybenzimidazole(PBI),sulfonated polyetheretherketone(SPEEK) and their composites are being investigated for high temperature and low RH operation with sufficient conductivities. We take a critical view and a surface protonic approach to gain fundamental insight.

• Sun, Xinwei; Chatzitakis, Athanasios Eleftherios & Norby, Truls Eivind (2019). Polymer-ceramic composite membranes for intermediate temperature PEM fuel cells.
• Sun, Xinwei & Norby, Truls Eivind (2019). Hydrogen og hydrogenteknologi.
• Vijayan Sobhana, Dilimon; Xing, Wen & Norby, Truls Eivind (2019). Electrode reactions on a molten carbonate Gd-doped CeO2 composite electrolyte. Show summary

  The complex chemical and electrochemical reactions involving CO2 and O2 at the cathode generally determine the overall performance of molten carbonate fuel cells (MCFCs) [1,2]. Experimental reports on the cathodic reactions consider merely the ions in the bulk molten carbonate (e.g. peroxide, superoxide, and peroxycarbonate ions, in addition to carbonate ions). Recently Czelej et al. used DFT calculations to investigate the MCFC cathode reactions at the perimeter of a triple phase boundary (TPB) of electronically conducting NiO, ionically conducting molten electrolyte, and pore space with reactant gases [1,2]. They showed a sequential Mars-van Krevelen and Eley-Rideal mechanism involving cathodic transformation of CO2 to CO32- via direct interaction of CO2 with the O-terminated octopolar NiO(111). Electrode reactions on a composite electrolyte with molten carbonate and ceramic oxide ion conductor have so far not been studied, however. In the present work, Gd-doped ceria (GDC) based composite membranes prepared by infiltration of Li2CO3-Na2CO3 eutectic molten phase in a pre-sintered porous GDC matrix were studied in the temperature range 575–675oC by electrochemical impedance spectroscopy (EIS) to characterize electrode reactions on them. A symmetrical cell configuration comprising two painted porous gold electrodes was used for the study. Three time constants associated with electrode processses were identified. The slowest process, with an activation energy of 130 kJ/mol showed a positive partial pressure dependency of exchange current density for O2, whereas the dependency was negative for CO2. Possible mechanisms are derived and discussed. References 1. K. Czelej et al., J. Mater. Chem. A 5 (2017) 13763-13768. 2. K. Czelej et al., Appl. Catal. B 222 (2018) 73–75.

• Vøllestad, Einar; Sørby, Magnus Helgerud & Norby, Truls Eivind (2019). Defect chemistry of mixed conducting double perovskites.
• Xu, Kaiqi; Chatzitakis, Athanasios Eleftherios; Norby, Truls Eivind & Bjørheim, Tor Svendsen (2019). Ta3N5 nanotubes loaded with Co(OH)x/Co-Pi-high photocurrent densities and improved photocorrosion resistance.
• Xu, Kaiqi; Grandcolas, Mathieu; Yang, Juan; Mei, Sen; Chatzitakis, Athanasios Eleftherios & Norby, Truls Eivind (2019). Photoelectrochemical water splitting on Ta3N5 nanotubes for H2 production.

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