Synthesis of Pt(WC) Catalysts for the Hydrogen Evolution Reaction (HER) by Platinum Deposition under Open Circuit Conditions

Abstract

Pt(WC_{1 – x})/Cu electrodes are obtained by depositing platinum onto the surface of tungsten carbides under open circuit conditions. A tungsten carbide layer with a thickness of ca. 20 μm is formed preliminarily on the surface of copper plates by the thermolysis of a gas mixture WF₆ + H₂ + C₃H₈. During the open-circuit deposition, platinum nanoparticles are formed on the surface of tungsten carbides. The oxidation of surface layers of tungsten carbides provides the electrons to reduce Pt(II) compounds. The morphology of thus prepared electrodes is studied using scanning electron microscopy (SEM). The chemical composition of the surface layers is studied using X-ray photoelectron spectroscopy (XPS). The phase composition is studied using X-ray phase analysis (XRD). The deposition of small amounts of platinum (0.002–0.24 mg Pt/cm² of the geometric electrode surface) gives rise to a significant increase in the hydrogen evolution reaction (HER) rate. The catalytic activity for the sample loaded with 0.24 mg/cm² platinum approaches that of a Pt/Pt electrode. The HER voltammetric characteristics on these Pt(WC_{1 – x})/Cu electrodes are determined. The hydrogen evolution is assumed to proceed on the catalytically active platinum nanoparticles.