Three electron channels toward two types of active sites in MoS2@Pt nanosheets for hydrogen evolution

Abstract

Molybdenum disulfide (MoS₂) has emerged as a promising electrocatalyst for the hydrogen evolution reaction (HER), but its activity generally suffers from limited edge active sites and stagnant conductivity. Here we report a controllable Pt decoration strategy on MoS₂ nanosheet arrays (NSAs) anchored on three-dimensional (3D) conductive carbon fiber cloth (CFC) substrates to boost the electrocatalytic HER activity to an upper level comparable to commercial Pt foil catalysts in acidic media, with a low overpotential of −70 mV and a Tafel slope of 36 mV per decade as well as a large exchange current density of 0.43 mA cm⁻². The results show that laden Pt makes the inert basal surface of MoS₂ an attractive platform steering three electron channels toward two types of active sites, that is, electron transfer from CFC to MoS₂ edge sites and surface Pt sites, as well as photo-excited electron injection from MoS₂ domains to adjacent Pt sites, promising an excellent HER performance. This study presents a feasible approach to boost the HER activity of MoS₂ through surface decoration activating the inert basal surface and provides deep insights for designing MoS₂-based HER catalysts.