Great wall structure inspired 2D@2D hetero-layered W-doped MoS2 for an enhanced hydrogen evolution reaction

Abstract

Doping engineering of 2D layered molybdenum disulfide (MoS₂) results in attractive catalytic activity for the hydrogen evolution reaction (HER); however, it is limited by its unclear mechanisms. Herein, inspired by the Great Wall structure, this work reports 2D@2D hetero-layered MoS₂/graphene nanosheets with rational modulation of W doping through the hydrothermal method. Results indicate that an optimal W doping of 12.5% in W_0.125Mo_0.875S₂-G presents the highest catalytic activity, which delivers the lowest overpotential of 306 mV at 100 mA cm⁻² and a Tafel slope of 62.2 mV dec⁻¹. Compared to W_0.125Mo_0.875S₂, W_0.125Mo_0.875S₂-G exhibits enhanced HER performance owing to the introduction of graphene. Theoretical calculation results indicate that the density of states (DOS) intensity near the Fermi level was enhanced with W doping, thus resulting in faster reaction kinetics. Our work provides new insights into the electrocatalytic mechanism of doping engineering of MoS₂ for an efficient HER.