Local atomic order in low Pt-content nanocatalysts investigated in situ by XAS

The unique features of X-ray absorption spectroscopy allow investigations of nanosized catalysts for fuel cells under working conditions. We present the results of an experiment carried out on a low Pt content electrocatalyst supported by a mesoporous heteropolyacid salt and used at the cathode of a proton exchange membrane fuel cell (PEMFC). The analysis of the EXAFS signal at the Pt L3-edge indicates that upon operating the fuel cell a substantial oxygen desorption from the Pt catalytic surface occurs followed by a tangible structural change on the Pt local order.