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

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.