Preferentially (100) oriented Pt thin film with less than a monolayer of Bi, Pd and Sb adatoms: application for formic acid oxidation

Abstract

The electrocatalytic properties of Bi, Sb and Pd decorated preferentially (100) oriented Pt thin films, denoted thereafter as Pt(100)pref, for the oxidation of formic acid are investigated. Pt(100)pref - Bi and Pt(100)pref - Sb are prepared by spontaneous adsorption in Bi+3 and Sb+3 saturated solution, and the coverage is controlled by varying the adsorption time. In both cases, less than a monolayer is deposited. In contrast, the deposition of a monolayer of Pd on Pt(100)pref is achieved by underpotential deposition and galvanic exchange reaction with a pre-deposited monolayer of Cu. For short electrolysis period (t<5s), the activity of the electrode for the oxidation of formic acid follows the order Pt(100)pref–Pd ML > Pt(100)pref–Sb (θ=75%) > Pt(100)pref–Bi (θ=88%) > > Pt(100)pref. However, after one hour of electrolysis, the Sb- and Bi-decorated Pt(100)pref electrode outperform both the Pd- decorated and the bare Pt(100)pref electrode (20, 15, 1 and 0.1mAcm−2geometric, respectively).