MoS2 on topological insulator Bi2Te3 thin films: Activation of the basal plane for hydrogen reduction

Abstract 2H-MoS2 is a well-studied and promising non-noble metal electrocatalyst for heterogeneous reactions, such as the hydrogen evolution reaction (HER). The performance is largely limited by the chemically inert basal plane, which is unfavorable for surface adsorption and reactions. Herein, we report a facile method to boost the HER activities of 2H-MoS2 by coupling with epitaxial Bi2Te3 topological insulator films. The as-obtained MoS2/ Bi2Te3/SrTiO3 catalyst exhibits prominent HER catalytic activities compared to that of pure MoS2 structures, with a 189 mV decrease in the overpotential required to reach a current density of 10 mA cm−2 and a low Tafel slope of 58 mV dec−1. Theoretical investigations suggest that the enhanced catalytic activity originates from the charge redistribution at the interface between the Bi2Te3topological insulator films and the MoS2 layer. The delocalized sp-derived topological surface states could denote electrons to the MoS2 layer and activate the basal plane for hydrogen adsorption. This study demonstrates the potential of manipulating topological surface states to design high-performance electrocatalysts.