A new compound Pt3Bi2S2 with superior performance for the hydrogen evolution reaction.

The exploration of efficient electrocatalysts for the hydrogen evolution reaction (HER) is beneficial to obtain renewable clean energy. Herein, a new parkerite-type compound Pt3Bi2S2 was synthesized, constructed by [PtBi4S2] octahedra. The Bi 6p orbital electrons upshift the Pt 5d band to promote hydrogen adsorption. Moreover, the Bi-Pt orbital hybridization greatly improves the conductivity and accelerates the charge transfer during the electrocatalytic process. Hence, Pt3Bi2S2 exhibits a superior catalytic activity for the HER with a low overpotential of 61 mV (at j = 10 mA cm-2) and a Tafel slope of 51 mV dec-1. In addition, Pt3Bi2S2 has higher stability than commercial Pt/C. This work proposes a promising strategy for designing new excellent HER catalysts.