Athanasios Chatzitakis

• Liu, Xin; Risbakk, Sanne; Almeida Carvalho, Patricia; Yang, Mingyi; Backe, Paul Hoff & Bjørås, Magnar [Show all 8 contributors for this article] (2022). Immobilization of FeFe-hydrogenase on black TiO2 nanotubes as biocathodes for the hydrogen evolution reaction. Electrochemistry communications. ISSN 1388-2481. 135. doi: 10.1016/j.elecom.2022.107221. Full text in Research Archive
• Kang, Xiaolan; Chatzitakis, Athanasios; Aarholt, Thomas; Sun, Xinwei; Negri, Chiara & Norby, Truls (2022). Facet-engineered TiO<inf>2</inf>nanomaterials reveal the role of water-oxide interactions in surface protonic conduction. Journal of Materials Chemistry A. ISSN 2050-7488. 10(1), p. 218–227. doi: 10.1039/d1ta06075a.
• Touni, Aikaterini; Liu, Xin; Kang, Xiaolan; Almeida Carvalho, Patricia; Diplas, Spyridon & Both, Kevin Gregor [Show all 8 contributors for this article] (2021). Galvanic Deposition of Pt Nanoparticles on Black TiO2 Nanotubes for Hydrogen Evolving Cathodes. ChemSusChem. ISSN 1864-5631. 14(22), p. 4993–5003. doi: 10.1002/cssc.202101559. Full text in Research Archive
• Kang, Xiaolan; Chaperman, Larissa; Galeckas, Augustinas; Ammar, Souad; Mammeri, Fayna & Norby, Truls [Show all 7 contributors for this article] (2021). Water Vapor Photoelectrolysis in a Solid-State Photoelectrochemical Cell with TiO2 Nanotubes Loaded with CdS and CdSe Nanoparticles. ACS Applied Materials & Interfaces. ISSN 1944-8244. 13(39), p. 46875–46885. doi: 10.1021/acsami.1c13047. Full text in Research Archive
• Zhu, Junjie; Gudmundsdottir, Jonina Björg; Strandbakke, Ragnar; Both, Kevin Gregor; Aarholt, Thomas & Almeida Carvalho, Patricia [Show all 12 contributors for this article] (2021). Double Perovskite Cobaltites Integrated in a Monolithic and Noble Metal-Free Photoelectrochemical Device for Efficient Water Splitting. ACS Applied Materials & Interfaces. ISSN 1944-8244. 13(17), p. 20313–20325. doi: 10.1021/acsami.1c01900. Full text in Research Archive
• Kang, Xiaolan; Berberidou, Chrysanthi; Galeckas, Augustinas; Bazioti, Kalliopi; Sagstuen, Einar & Norby, Truls Eivind [Show all 8 contributors for this article] (2021). Visible Light Driven Photocatalytic Decolorization and Disinfection of Water Employing Reduced TiO2 Nanopowders. Catalysts. ISSN 2073-4344. 11(2). doi: 10.3390/catal11020228. Full text in Research Archive
• Chaguetmi, Samiha; Chaguetmi, Salem; Sobti, Nadjah; Belkahla, Hanène; Chaperman, Larissa & Chatzitakis, Athanasios Eleftherios [Show all 9 contributors for this article] (2020). Enhancement of the photoelectrochemical properties of TiO2 nanofibers supported on Ti sheets by polyol-made CdSe quantum-dots impregnation. Materials Letters. ISSN 0167-577X. 273. doi: 10.1016/j.matlet.2020.127934.
• 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
• 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.
• 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. doi: 10.1016/j.electacta.2020.135743. Full text in Research Archive
• Andersen, Håkon; Xu, Kaiqi; Malyshkin, Dmitry; Strandbakke, Ragnar & Chatzitakis, Athanasios Eleftherios (2020). A highly efficient electrocatalyst based on double perovskite cobaltites with immense intrinsic catalytic activity for water oxidation. Chemical Communications. ISSN 1359-7345. 56(7), p. 1030–1033. doi: 10.1039/c9cc08765f.
• Xu, Kaiqi; Chatzitakis, Athanasios Eleftherios; Risbakk, Sanne; Yang, Mingyi; Backe, Paul Hoff & Grandcolas, Mathieu [Show all 8 contributors for this article] (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
• 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), p. 21391–21940. doi: 10.1021/acs.jpcc.9b05070.
• Chatzitakis, Athanasios Eleftherios & Longela, Simon Makusudi (2019). Electrochemical characterisation of bovine serum albumin adsorption on phenolic- coated nickel-titanium. Journal of Engineering Science and Technology Review. ISSN 1791-9320. 12(2), p. 1–8. doi: 10.25103/jestr.122.01.
• 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.
• Grandcolas, Mathieu; Wabende, Brian; Yang, Juan; Mei, Sen; Xu, Kaiqi & Norby, Truls Eivind [Show all 7 contributors for this article] (2019). Preparation of TiO2 rutile nanorods decorated with cobalt oxide nanoparticles for solar photoelectrochemical activity. Materials Letters. ISSN 0167-577X. 247, p. 1–3. doi: 10.1016/j.matlet.2019.03.087. 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, p. 187–196. doi: 10.1016/j.electacta.2019.03.058.
• Chatzitakis, Athanasios Eleftherios & Sartori, Sabrina (2019). Recent Advances in the Use of Black TiO2 for Production of Hydrogen and Other Solar Fuels. ChemPhysChem. ISSN 1439-4235. 20(10), p. 1272–1281. doi: 10.1002/cphc.201801094. 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), p. 587–593. doi: 10.1016/j.ijhydene.2018.11.030. 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), p. 837–844. doi: 10.1039/c8pp00312b. Full text in Research Archive
• Sun, Xinwei; Xu, Kaiqi; Fleischer, Christian; Liu, Xin; Grandcolas, Mathieu & Strandbakke, Ragnar [Show all 9 contributors for this article] (2018). Earth-abundant electrocatalysts in proton exchange membrane electrolyzers. Catalysts. ISSN 2073-4344. 8:657(12), p. 1–41. doi: 10.3390/catal8120657. Full text in Research Archive Show summary

  In order to adopt water electrolyzers as a main hydrogen production system, it is critical to develop inexpensive and earth-abundant catalysts. Currently, both half-reactions in water splitting depend heavily on noble metal catalysts. This review discusses the proton exchange membrane (PEM) water electrolysis (WE) and the progress in replacing the noble-metal catalysts with earth-abundant ones. The efforts within this field for the discovery of efficient and stable earth-abundant catalysts (EACs) have increased exponentially the last few years. The development of EACs for the oxygen evolution reaction (OER) in acidic media is particularly important, as the only stable and efficient catalysts until now are noble-metal oxides, such as IrOx and RuOx. On the hydrogen evolution reaction (HER) side, there is significant progress on EACs under acidic conditions, but there are very few reports of these EACs employed in full PEM WE cells. These two main issues are reviewed, and we conclude with prospects for innovation in EACs for the OER in acidic environments, as well as with a critical assessment of the few full PEM WE cells assembled with EACs.

• Fleischer, Christian; Chatzitakis, Athanasios Eleftherios & Norby, Truls Eivind (2018). Intrinsic photoelectrocatalytic activity in oriented, photonic TiO2 nanotubes. Materials Science in Semiconductor Processing. ISSN 1369-8001. 88, p. 186–191. doi: 10.1016/j.mssp.2018.08.009. Show summary

  In this work, we grow oriented photonic TiO2 nanotubes (TNTs) with a well-established anodization method and their intrinsic catalytic and electronic properties are studied by means of (photo)electrochemical methods. The oriented photonic TNTs are assessed by the RctCdl (ΩF) product, which is a measure of the intrinsic photoelectrocatalytic activity (IPA) of the material. The RctCdl product decouples any surface area effects and it can be applied at any potential and accompanied reaction without knowing the actual electrochemically active surface area (EASA). Moreover, electrochemical impedance spectroscopy (EIS) is used in order to investigate the frequency dispersion in the single frequency Mott-Schottky (MS) measurement. The choice of frequency and the frequency dispersion in MS measurements in nanostructured and of high surface area semiconductors are rarely addressed and can result in erroneous values of two important parameters, i.e. flat band position and donor or acceptor densities. This work provides further insights into important electrochemical aspects and catalytic properties of high surface area nanomaterials for photoelectrochemical applications.

• Longela, Simon M & Chatzitakis, Athanasios Eleftherios (2017). In vitro corrosion behaviour of phenolic coated nickel-titanium surfaces. Biosurface and Biotribology. ISSN 2405-4518. 6(1), p. 25–30. doi: 10.1016/j.bsbt.2017.10.002.
• Chatzitakis, Athanasios Eleftherios; Grandcolas, Mathieu; Xu, Kaiqi; Mei, Sen; Yang, Juan & Jensen, Ingvild Julie Thue [Show all 8 contributors for this article] (2017). Assessing the photoelectrochemical properties of C, N, F codoped TiO2 nanotubes of different lengths. Catalysis Today. ISSN 0920-5861. 287, p. 161–168. doi: 10.1016/j.cattod.2016.11.040. Full text in Research Archive Show summary

  The aim of this work has been the photoelectrochemical (PEC) study of nanostructured photoanodes based on TiO2. Highly ordered and well adhered TiO2 nanotubes (TNTs) of different lengths (∼2–20 μm) were prepared in a two-step process in ethylene glycol solutions containing fluorides, and detailed XPS analysis showed that they have become co-doped with C, N and F. PEC measurements revealed that increasing surface area is not followed by increase in the photoconversion efficiency, but rather that an optimal balance between electroactive surface area (ESA) and charge carrier concentration exists. TNTs of around 10 μm show the optimum incident photon-to-current efficiency (IPCE) of ∼33% and an overall photoconversion efficiency of ∼6.3% under UV illumination of 4 mW cm−2 light intensity. Finally, Mott-Schottky analysis revealed significant frequency dispersion of the estimated space charge layer capacitance, which renders the accurate estimation of the flatband position and charge carrier concentration unreliable. On the other hand, more realistic charge carrier concentrations can be obtained by normalizing the capacitance per ESA.

• Xu, Kaiqi; Chatzitakis, Athanasios Eleftherios & Norby, Truls (2017). Solid-state photoelectrochemical cell with TiO2 nanotubes for water splitting. Photochemical and Photobiological Sciences. ISSN 1474-905X. 16(1), p. 10–16. doi: 10.1039/c6pp00217j. Full text in Research Archive

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• Kuvshinov, Mikhail; Karazhanov, Smagul; Hallsteinsen, Ingrid & Chatzitakis, Athanasios (2021). Synthesis and characterization of Ni-Mo alloy for applications as cathodes in photoelectrochemical (PEC) cells.
• Chatzitakis, Athanasios (2021). Solar Hydrogen Production.
• Chaperman, Larissa; Mammeri, Fayna; Chatzitakis, Athanasios & Ammar, Souad (2021). Functionally graded, soft chemistry processed titania photoanode for water-splitting in liquid and gas phases.
• Chatzitakis, Athanasios (2021). Fuel(s) from the Sun.
• Karazhanov, Smagul; Zavorotynska, Olena & Chatzitakis, Athanasios (2021). Organizing online international school "Materials and processes for production of solar hydrogen" within the “Complex of online and onsite lectures on materials for hydrogen generation by solar water splitting” med acronym” (COOL LONGBOAT) project.
• Karazhanov, Smagul; Zavorotynska, Olena & Chatzitakis, Athanasios (2021). Book of abstracts of the online international school "Materials and processes for production of solar hydrogen".
• Touni, Aikaterini; Liu, Xin; Chatzitakis, Athanasios Eleftherios; Kang, Xiaolan; Spyridou, Olga & Sotiropoulos, Sotiris (2021). Platinized Black Titania Nanotube HER Cathodes prepared by the Galvanic Deposition Method at CaH2-reduced Titania Nanotubes.
• Liu, Xin; Risbakk, Sanne; Almeida Carvalho, Patricia; Yang, Mingyi; Backe, Paul Hoff & Bjorås, Magnar [Show all 8 contributors for this article] (2020). Hydrogenase-assisted catalysis on titania electrode oxides.
• Xu, Kaiqi; Chatzitakis, Athanasios Eleftherios; Backe, Paul Hoff; Ruan, Qiushi; Tang, Junwang & Bjørås, Magnar [Show all 8 contributors for this article] (2020). The use of NMR to assess the activity of formate dehydrogenase biocatalysts for CO2 utilization.
• Chatzitakis, Athanasios Eleftherios (2019). Prospects of photoelectrochemical water electrolysis and the production of solar fuels.
• Liu, Xin; Chatzitakis, Athanasios Eleftherios; Almeida Carvalho, Patricia; Risbakk, Sanne; Yang, Mingyi & Backe, Paul Hoff [Show all 7 contributors for this article] (2019). Enzyme-assisted Catalysis on Titania Electrodes.
• 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 .
• Chatzitakis, Athanasios Eleftherios (2019). Artificial Photosynthesis: Mimicking nature for a sustainable energy future.
• Chatzitakis, Athanasios Eleftherios (2019). Can we make fuel in the future from… simply air? .
• 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.
• Xu, Kaiqi; Grandcolas, Mathieu; Yang, Juan; Mei, Sen; Chatzitakis, Athanasios Eleftherios & Norby, Truls Eivind (2019). Photoelectrochemical water splitting on Ta3N5 nanotubes for H2 production .
• Liu, Xin; Chatzitakis, Athanasios Eleftherios; Almeida Carvalho, Patricia; Backe, Paul Hoff; Yang, Mingyi & Bjørås, Magnar [Show all 7 contributors for this article] (2018). Enzyme-assisted Catalysis on Black Titania Electrodes.
• Sun, Xinwei; Xu, Kaiqi; Chatzitakis, Athanasios Eleftherios & Norby, Truls Eivind (2018). Can hydroxyl radicals travel far? Gas phase transport and detection after photocatalytic generation at TiO2 nanorods.
• Xu, Kaiqi; Chatzitakis, Athanasios Eleftherios; Vøllestad, Einar; Ruan, Qiushi; Tang, Junwang & Norby, Truls Eivind (2018). Solid-state tandem photoelectrochemical cell for wet air electrolysis and hydrogen production .
• Xu, Kaiqi; Chatzitakis, Athanasios Eleftherios; Bjørheim, Tor Svendsen & Norby, Truls Eivind (2018). Surface modification of Ta3N5 nanotubes as photocatalyst for photoelectrochemical water splitting.
• Chatzitakis, Athanasios Eleftherios; Simonsen, Stian; Fontaine, Marie Laure; Thomassen, Magnus & Norby, Truls Eivind (2018). Conductivity of polymer-ceramic composite membranes at high T and p(H2O) using a novel PEEK sample holder.
• Xu, Kaiqi; Chatzitakis, Athanasios Eleftherios; Vøllestad, Einar; Ruan, Qiushi; Tang, Junwang & Norby, Truls Eivind (2018). Solid-state photoelectrochemical cell for wet air electrolysis and hydrogen production.
• Xu, Kaiqi; Chatzitakis, Athanasios Eleftherios; Norby, Truls Eivind; Grandcolas, Mathieu; Yang, Juan & Mei, Sen (2018). Ta3N5 / Co(OH)x composite as the photocatalyst for photoelectrochemical water splitting.
• Grandcolas, Mathieu; Wabende, Brian; Yang, Juan; Mei, Sen; Xu, Kaiqi & Chatzitakis, Athanasios Eleftherios [Show all 7 contributors for this article] (2018). TiO2 Nanorods Decorated With Cobalt oxide as Photoanodes for a Bio-Hybrid PEC Cell.
• Fontaine, Marie-Laure; Chatzitakis, Athanasios Eleftherios; Vøllestad, Einar; Thomassen, Magnus & Norby, Truls Eivind (2018). Principles of proton conduction in polymer-ceramic composite membranes for PEM applications.
• Chatzitakis, Athanasios Eleftherios (2017). (Photo)electrochemical applications of TiO2 nanotubes .
• Fleischer, Christian; Chatzitakis, Athanasios Eleftherios; Grandcolas, Mathieu; Mei, Sen & Norby, Truls Eivind (2017). Solid-state photoelectrochemical water splitting: Application and properties of TiO2 nanotubes.
• Xu, Kaiqi; Chatzitakis, Athanasios Eleftherios; Norby, Truls Eivind; Mei, Sen; Juan, Yang & Grandcolas, Mathieu [Show all 7 contributors for this article] (2017). Solid-state photoelectrochemical Cell with Tantalum Nitride Nanotubes as Photoanode.
• Yang, Juan; Mei, Sen; Grandcolas, Mathieu; Simon, Christian; Xu, Kaiqi & Chatzitakis, Athanasios Eleftherios [Show all 10 contributors for this article] (2017). Synthesis of Nanosized Cobalt Oxides and Application in a Bio-hybrid Photoelectrochemical Cell for CO2 Utilization. Show summary

  CO2 capture and utilization (CCU) can alleviate the disastrous effects of greenhouse gas (GHG) emissions form the use of fossil fuels. The use of CO2 emission as feedstock for direct conversion into valuable chemicals has attracted increasing research interest worldwide. A number of approaches, such as chemical, electrochemical, photochemical and biological routes have used CO2 as a sustainable carbon resource for the production of chemicals. In the present CO2BioPEC project, a novel hybrid photoelectrochemical concept, based on solar energy and formate dehydrogenase biocatalyst is applied, as illustrated in Figure 1 (left). This multidisciplinary project aims at demonstrating a bio-hybrid photoelectrochemical cell, in which solar energy is efficiently captured and utilized to convert CO2 into energy-rich compounds, using formate dehydrogenase enzymes as biocatalysts. Cobalt oxide is a low-cost material with a band gap that can absorb visible light. It is also a promising co-catalyst that has been widely used for oxygen evolution route. In the present work, nanosized cobalt oxide was synthesized and used as a co-catalyst on the photoanode. The results showed that the formation of cobalt oxides (Co3O4, CoOOH and Co(OH)2) is strongly dependent on the temperature and reaction time. The photochemical efficiency will be further investigated by impregnating nanosized cobalt oxides onto Ta3N4 /TaON nanotubes.

• Chatzitakis, Athanasios Eleftherios; Xu, Kaiqi & Norby, Truls Eivind (2017). TiO2 nanotubes as photoanode electrodes in solid-state photoelectrochemical cells.
• Xu, Kaiqi; Chatzitakis, Athanasios Eleftherios; Bjørheim, Tor Svendsen & Norby, Truls Eivind (2017). Tantalum oxynitride for photoelectrochemical water splitting.
• Xu, Kaiqi; Chatzitakis, Athanasios Eleftherios; Bjørheim, Tor Svendsen & Norby, Truls Eivind (2017). Fuels from the sun, sea and air-by solid-state photoelectrochemical cell.
• Fleischer, Christian; Xu, Kaiqi; Chatzitakis, Athanasios Eleftherios & Norby, Truls Eivind (2016). Development of high surface area TiO2 photo-electrodes and the significance of solid-state proton conductor in water splitting photoelectrochemical cell.
• Grandcolas, Mathieu; Sahoo, Prangya Parimita; Foss, Carl Erik Lie; Xing, Wen; Polfus, Jonathan M. & Sunde, Svein [Show all 8 contributors for this article] (2016). Novel photoelectrocatalytic concepts for conversion of nitrogen to fuels and chemicals.
• Xu, Kaiqi; Chatzitakis, Athanasios Eleftherios & Norby, Truls (2016). An All-Solid-State Photoelectrochemical Cell for Water Splitting.
• Chatzitakis, Athanasios Eleftherios; Grandcolas, Mathieu; Xu, Kaiqi; Mei, Sen; Yang, Juan & Simon, Christian [Show all 7 contributors for this article] (2016). Assessing the photoelectrocatalytic activity of C, N, F codoped TiO2 nanotubes of different lengths for oxygen evolution.
• Chatzitakis, Athanasios Eleftherios & Norby, Truls (2015). Solar hydrogen production.
• Chatzitakis, Athanasios Eleftherios & Norby, Truls (2015). Solid electrolytes for photoelectrochemical cells.
• Chatzitakis, Athanasios Eleftherios; Xu, Kaiqi; Boye, Ole; Backe, Paul Hoff; Bjorås, Magnar & Dalhus, Bjørn [Show all 13 contributors for this article] (2015). Solar based H2 generation in a novel photoelectrochemical-enzymatic hybrid cell.
• Kang, Xiaolan; Norby, Truls & Chatzitakis, Athanasios (2021). Novel nanostructured materials for energy applications. Universitetet i Oslo, Det matematisk-naturvitenskapelige fakultet. ISSN 1501-7710. 2021(2465). Show summary

  Nanomaterials and nanotechnology have been flourishing greatly over the last decades and their applications are spreading almost over all the branches of science and technology. In this work, we zoomed into the synthesis and characterization of nanostructured materials. The central focus was to manipulate the compositions, morphology and structures of nanomaterials by combining various strategies like defect engineering and exsolution. Several interesting features and properties of nanostructured materials were investigated and highlighted, including the optical, plasmonic, electronic and surface properties. This process deepened our fundamental understanding of surface protonic conduction of nanocrystalline oxides and increased our control over nanostructuring of materials in order to achieve targeted functionalities. The as-prepared nanomaterials have been applied in energy- and environment-related applications, showing improved and controllable efficiency in pollutants degradation and water (vapor) splitting in photocatalytic, (photo) electrocatalytic, as well as in a solid-state photoelectrocatalytic systems.

• Andersen, Karoline Sjøen; Norby, Truls; Sartori, Sabrina & Chatzitakis, Athanasios (2020). Hydrophobic coatings for offshore PV modules: Impact of precipitation from seawater on the protective glass. Department of Chemisty, UiO.
• Xu, Kaiqi; Norby, Truls Eivind; Chatzitakis, Athanasios Eleftherios & Bjørheim, Tor Svendsen (2020). Artificial photosynthesis – Advanced nanomaterials and use of biocatalysts for novel photoelectrochemical cells. Matematisk Naturvitenskapelig fakultet, Universitetet i Oslo. ISSN 1501-7710. 2020( 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.

• 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. Kjemisk Institutt, Universitetet i Oslo.
• Andreassen, Magnus Haga; Norby, Truls Eivind & Chatzitakis, Athanasios Eleftherios (2020). Synthesis, characterization, and optimization of Cu2O photocathodes for solid-state photoelectrochemical cells. Kjemisk Institutt, Universitetet i Oslo.
• Simonsen, Stian Christopher; Norby, Truls Eivind & Chatzitakis, Athanasios Eleftherios (2020). Nafion®-Ceramic Composite Electrolytes for Proton Exchange Membrane Fuel Cells at Elevated Temperatures. Kjemisk Institutt, Universitetet i Oslo.

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