Interfacial π–p Electron Coupling Prompts Hydrogen Evolution Reaction Activity in Acidic Electrolyte

The thermodynamically stable 2H-phase MoS₂ is a brilliant material toward hydrogen evolution reaction (HER) owing to its excellent Gibbs free energy of hydrogen adsorption. Nevertheless, the poor intrinsic properties of 2H-MoS₂ limit its electrocatalytic performances toward HER. In this work, graphitic carbon nitride covalently bridging 2H-MoS₂ (MoS₂/GCN) is proposed to construct robust HER electrocatalysts. The strong π–p electron coupling between the delocalized π electrons of GCN and the localized p electrons of S atoms sufficiently expose active sites and accelerate the reaction kinetics. To be specific, MoS₂/GCN exhibits remarkable HER activity (160 mV at 10 mA·cm^–2) and long-term durability. Importantly, MoS₂/GCN also provides great potential for industrial application. Density functional theory (DFT) calculations disclose that the π–p electron coupling at the MoS₂/GCN interface regulates the electronic structure of S atoms, consequently providing enhanced HER performance. This work presents a feasible pathway to develop advanced electrocatalysts for energy conversions.