J. Drnec, D. Bizzotto, F. Carlà, R. Fiala, A. Sode, O. Balmes, B. Detlefs, T. Dufrane, R. Felici
Applied Surface Science, 354(2015), pp. 443–449
Publication year: 2015

The electrochemical formation and dissolution of the oxygen reduction reaction (ORR) PtZn catalyst on Pt(1 1 1) surface is followed by in-situ X-ray diffraction (XRD) and X-ray reflectivity (XRR) measurements. When the crystalline Pt surface is polarized to sufficiently negative potential values, with respect to an Ag/AgCl|KCl reference electrode, the electrodeposited zinc atoms diffuse into the bulk and characteristic features are observed in the X-ray patterns. The surface structure and composition during deposition and dissolution is determined from analysis of XRR curves and measurements of crystal truncation rods. Thin Zn-rich surface layer is present during the alloy formation while a Zn-depleted layer forms during dissolution.