The Surface Processes on Ru/Pt(111) as Probed by Cyclic Voltammetry and in Situ Surface-Enhanced Raman Spectroscopy

Abstract

Information about the chemical adsorption and surface oxidation of Ru under electrochemical conditions is of great importance for understanding the structure-activity relationship in Ru-based materials. Quasi-single-crystalline Ru films on single-crystal Pt(111) electrodes (Ru/Pt(111)) were prepared by the forced-deposition method along with inductive heating treatment. The adsorption of both hydrogen and oxygen species on Ru/Pt(111) was studied by cyclic voltammetry and CO displacement. The potential of zero total charge on Ru/Pt(111) is ca. 0.12 V. A detailed study on oxygen species was carried out by in situ surface-enhanced Raman spectrometry. Ru-O was found to form at E > 0.1 V, and the conversion of Ru-O into RuO2occurred at E = 0.3 V. The reversible oxidation occurs up to 1.0 V. Our results suggest that Ru/Pt(111), which exhibits electrochemical properties similar to those of Ru(0001), may serve as an alternative for Ru study as well as a model system for understanding ligand and strain effects.