High-efficiency electrochemical hydrogen evolution based on the intermetallic Pt2Si compound prepared by magnetron-sputtering

Abstract

The development of highly active and stable electrocatalysts for the hydrogen evolution reaction (HER) is central to the area of renewable energy. Si nanocomposites exhibited high efficiency in a light-induced hydrogen evolution reaction. However, there are few reports on the experimental application of the electrochemical HER. Herein, we report a simple synthesis of an intermetallic Pt₂Si electrode using magnetron sputtering (MS) synthesis. The physical and electrochemical characterization of the materials was achieved by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray fluorescence (XRF), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Herein, the electrochemical catalytic activity towards the HER of an intermetallic Pt₂Si MS (IM-Pt₂Si-MS) electrode is demonstrated for the first time. Cyclic voltammetry (CV) curves reveal that the H underpotential deposition (H-UPD) peaks of the IM-Pt₂Si-MS electrode shift to higher potentials than those of a Pt electrode, which indicates that hydrogen is more easily adsorbed on the Pt₂Si surface. Thus, the IM-Pt₂Si-MS electrode exhibited a higher HER activity than that of a Pt electrode in 0.5 M H₂SO₄ solution through linear sweep voltammetry (LSV). This is attributed to the electronic structure modification of Pt and the synergistic effect of the Pt–Si binary alloy in the IM-Pt₂Si-MS electrode. In addition, the Tafel slope of 30.5 mV dec⁻¹ indicates that the mechanism for the Pt₂Si-catalyzed HER is Volmer–Tafel, for which the combined desorption of hydrogen is the rate-limiting step.