PtRu Alloy and PtRu−WO3 Nanocomposite Electrodes for Methanol Electrooxidation Fabricated by a Sputtering Deposition Method

Abstract

PtRu alloy and PtRu−WO3 nanocomposite thin-film electrodes for methanol electrooxidation were fabricated by means of a sputtering method. The structural and electrochemical properties of well-defined PtRu alloy thin-film electrodes were characterized using X-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy, and electrochemical measurements. The alloy thin-film electrodes were classified as follows: Pt-based (10−40 atom % of Ru) and Ru-based (60 atom % of Ru) alloy structure. Among the electrodes formed by the sputtering method, PtRu-80, with 62 atom % Pt confirmed by XRD, showed the best catalytic activity for methanol electrooxidation. In particular, surface enrichment of Pt in the PtRu alloy thin-film electrodes, e.g. 65 atom % Pt for PtRu-80, was observed by XPS. Then, based on structural and electrochemical understanding of the PtRu alloy electrodes, PtRu−WO3 nanocomposite thin-film electrodes were formed. Th...