Alexander K Opitz

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For application of acceptor-doped mixed conducting oxides as solid oxide fuel cell (SOFC) anodes, high electrochemical surface activity as well as acceptable electronic and ionic conductivity are crucial. In a reducing atmosphere, particularly the electronic conductivity of acceptor-doped oxides can become rather low and the resulting complex interplay of(More)
Owing to its mixed ionic and electronic conductivity and high thermochemical stability, La0.6Sr0.4FeO3-δ (LSF64) is an attractive electrode material in solid oxide fuel/electrolysis cells (SOFCs/SOECs). Well defined thin film microelectrodes are used to compare the electrochemical properties of LSF64 in oxidizing and reducing conditions. The high electronic(More)
In the search for optimized cathode materials for high-temperature electrolysis, mixed conducting oxides are highly promising candidates. This study deals with fundamentally novel insights into the relation between surface chemistry and electrocatalytic activity of lanthanum ferrite based electrolysis cathodes. For this means, near-ambient-pressure X-ray(More)
The oxygen exchange activity of mixed conducting oxide surfaces has been widely investigated, but a detailed understanding of the corresponding reaction mechanisms and the rate-limiting steps is largely still missing. Combined in situ investigation of electrochemically polarized model electrode surfaces under realistic temperature and pressure conditions by(More)
Article history: Received 27 July 2015 Received in revised form 7 January 2016 Accepted 22 January 2016 Available online 26 January 2016 25 nm thick Gd-doped ceria thin films were grown on yttria-stabilized zirconia (YSZ) substrates with (110) and (111) orientation by pulsed laser deposition to study both their crystalline structure and interfacial(More)
In this study the electrochemically active region of oxygen incorporation into yttria stabilized zirconia (YSZ) was visualized by means of (18)O tracer incorporation experiments on dense Pt thin film microelectrodes combined with ToF-SIMS analysis. The localization and the shape of the incorporation zone were found to strongly depend on the polarization of(More)
Micro-patterned Ni thin films with well-defined 2D-structures are useful to examine electrochemical reaction kinetics of SOFC anodes. In this work, an electrode preparation method is developed yielding stable Ni pattern electrodes on YSZ, which facilitate long term measurements. Moreover, these stable electrodes allowed investigating the effect of the YSZ(More)