Monday 22 September 2014
to 11:00 at
Anders Nilsson (Molecular Physics Department)
I will demonstrate how electron and x-ray spectroscopy can be used to address fundamental questions regarding the reaction mechanism and active sites of the Oxygen Reduction Reaction (ORR), Oxygen Evolution Reaction (OER) and Hydrogen Evolution Reaction (HER). We have developed in-situ XPS capabilities using a membrane assembly where either the anode or cathode side is exposed to a differential pumped environments where direct measurements of the changes in the catalyst and various reaction intermediates can be probed during ORR on Pt, OER on IrO2 and HER conditions for MoS2. We have also recently conducted high-energy resolution fluorescence detection (HERFD) studies of the Fe and Ni K-edges under OES conditions in the highly active Ni-Fi oxyhydroxides to determine the nature of the active sites. In particular we observe that Fe encounter an extremely strained local geometry when Ni undergoes a transformation from the 2+ to 3+ state.