Simultaneously Engineering Electron Conductivity, Site Density and Intrinsic Activity of MoS₂ via the Cation and Anion Codoping Strategy

Abstract

The catalytic activity of 2H-MoS₂ is retarded by the deficiency in active sites, inferior intrinsic activity, and slow electron transfer kinetics. However, the strategies to concurrently resolve these issues have been challenging and rarely reported. Herein, we successfully endow MoS₂ with exceptional acidic HER performance by concurrently doping nitrogen and metal atoms into the basal plane of MoS₂. The experimental results reveal that the N dopant that induces the intervalence charge transfer between two ions (Mo⁴⁺/Mo³⁺) and the atoms rearrangement can enable the successful synthesis of 1T MoS₂ on reduced graphene oxides, which can concurrently increase the active-site density and facilitate the charge transfer from the substrate to the catalyst active sites. The spontaneous doping of metal cation atoms further improves the intrinsic activity of MoS₂ by creating more sulfur vacancy sites and tailoring the energy level matching. The optimized electrocatalyst exhibited unprecedented activity and stability for HER with a low overpotential of 143 mV at 150 mA cm^-2 and a high exchange current density of 1 mA cm^-2. Therefore, our work opens up possibility to manipulate the MoS₂ catalytic performance to rival Pt, which is of significant importance to both fundamental study and industry applications.