Christoph Rameshan

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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)
For use of polymer electrolyte membrane fuel cells (PEMFC) in mobile power applications, an efficient source of COdepleted hydrogen is needed. To avoid technical and safety problems of hydrogen handling, storage, and transport, methanol can be used as practical and abundant energy carrier for on-board H2 generation, as it has the advantage of a high energy(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)
Matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) measurements in the low-molecular-mass region, ranging from 0 to 1000 Daltons are very often difficult to perform because of signal interferences originating from matrix ions. In order to overcome this problem, a stainless steel target was coated with a homogeneous titanium dioxide(More)
The combination of (High-resolution) electron microscopy, Selected Area Diffraction and X-ray Diffraction was applied to study the structural, compositional and morphological alterations of two Pd/Ga2O3 catalysts relevant for methanol steam reforming upon different oxidative and reductive treatments. These systems include well-defined Pd particles grown(More)
We demonstrate the reversible intercalation of CO between a hexagonal boron nitride (h-BN) monolayer and a Rh(111) substrate above a threshold CO pressure of 0.01 mbar at room temperature. The intercalation of CO results in the flattening of the originally corrugated h-BN nanomesh and an electronic decoupling of the BN layer from the Rh substrate. The(More)
An ultra-high vacuum (UHV) setup for "real" and "inverse" model catalyst preparation, depth-resolved near-surface spectroscopic characterization, and quantification of catalytic activity and selectivity under technologically relevant conditions is described. Due to the all-quartz reactor attached directly to the UHV-chamber, transfer of the catalyst for in(More)
Ultrathin (∼3 Å) zirconium oxide films were grown on a single-crystalline Pt3Zr(0001) substrate by oxidation in 1 × 10 −7 mbar of O2 at 673 K, followed by annealing at temperatures up to 1023 K. The ZrO2 films are intended to serve as model supports for reforming catalysts and fuel cell anodes. The atomic and electronic structure and composition of the ZrO2(More)
Co3O4 is a promising catalyst for removing CO from H2 streams via the preferential CO oxidation (PROX). A Mars-van-Krevelen redox mechanism is often suggested but a detailed knowledge especially of the oxidation state of the catalytically active surface under reaction conditions is typically missing. We have thus utilized operando X-ray absorption(More)