0000000000639383
AUTHOR
Christoph J. Sahle
Dynamic Role of Gold d-Orbitals during CO Oxidation under Aerobic Conditions
High-energy-resolution fluorescence detection-X-ray absorption near-edge structure (HERFD-XANES) at the Au L3 edge was used to study gold catalysts supported on ceria in order to unravel the role of gold 5d orbital modifications during the activation of molecular oxygen. The variations in the HERFD-XANES resonance peak, which are directly correlated with the d-band occupancy, were monitored in situ during the redox process of the CO oxidation at room temperature under both aerobic and anaerobic conditions. Interestingly, upon the oxidation treatment and also during the aerobic CO oxidation treatment, the gold d-band fluctuates around an average value, proving that the gold clusters are part…
The Effect of Ni Doping on the Performance and Electronic Structure of LSCF Cathodes Used for IT-SOFCs
We investigated the effect of nickel doping on the electronic structure and performance of nanostructured La0.6Sr0.4Co0.2Fe0.8-0.03Ni0.03O3-delta prepared by the one-pot sol gel method. The commercial undoped La0.6Sr0.4Co0.2Fe0.8O3-delta (ISCF0.8) was used as reference. Moreover, for comparison, Ni (3 mol %) was deposited by wetness impregnation over the La0.6Sr0.4Co0.2Fe0.8O3-delta. We show by in situ X-ray absorption spectroscopy at 900 degrees C under air flow that nickel enters the B perovskite site of the material and favors the stabilization of the cobalt oxidation state, as evidenced by the delay in the decrease of the average Co valence with respect to undoped samples. Our results a…