Regenerating Pt–3d–Pt model electrocatalysts through oxidation–reduction cycles monitored at atmospheric pressure

The interchange between the Pt–Ni–Pt and Ni–Pt–Pt bimetallic configurations in O2 and H2 is confirmed experimentally at atmospheric pressure using in situ X-ray absorption spectroscopy (XAS). The subsurface Pt–3d–Pt structure, a desirable configuration as cathode electrocatalysts for PEM fuel cells, is found to be preferred in the reducing environment of H2 whereas the surface 3d–Pt–Pt configuration is preferred in O2. This process has been found to be reversible, providing useful insights into the maintenance and regeneration of the desirable subsurface structure.