Microscopic, spectroscopic and electrochemical characterization of the surface of Pd–Ag alloys

Thin layers (0.4 μm) of Pd-rich (⩾90 at.% Pd in the bulk) Pd–Ag alloys were prepared by electrodeposition on Au substrate. The surface of the alloys was characterized electrochemically (cyclic voltammetry) and by means of surface science techniques: scanning electron microscopy and Auger electron spectroscopy. For freshly deposited Pd–Ag electrodes surface enrichment with Ag was observed. The influence of hydrogen electrosorption on the composition of the alloy surface was investigated. It was found that hydrogen electrosorption significantly affects surface segregation process. This is probably the result of alloy surface reorganization induced by much stronger interactions of hydrogen with Pd than with Ag.