Formation of Hierarchical PtZn Alloy Films under Highly Cathodic Polarization of Pure Pt in a Dilute ZnSO₄ Solution and Their Electrocatalytic Applications

摘要

In this paper, hierarchical and high-rough PtZn alloy films were cathodically fabricated from a smoothPt substrate in an alkaline aqueous solution of low ZnSO4 concentration at a moderate temperature ofo 40 C. Subsequently, the Pt/Zn atomic ratios for the films were regulated by dissolution of bulk Zn andpartial dealloying of alloyed Zn in a H2SO4 solution under lower and higher anodic potentials,respectively. The films were characterized by scanning electron microscopy (SEM), energy dispersiveX-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The film formation might beclosely related to processes including Zn electrodeposition, PtZn alloying, hydrogen evolution andcathodic corrosion of Pt under highly cathodic polarization. The as-prepared films exhibit betterelectrocatalytic activities toward the oxidation of formic acid and methanol, as compared with smoothPt and PtZn films prepared under less cathodic polarization (without hydrogen evolution).