Nitrogen-induced interfacial electronic structure with optimized water and hydrogen binding abilities for efficient alkaline hydrogen evolution electrocatalysis

Fabricating heterostructures with dense interfacial catalytic sites is vitally essential for implementation of high-performance hydrogen evolution reaction (HER). However, the strong correlation between the adsorbed hydrogen atoms and electronegative nonmetal atoms gives rise to the unfavorable hydrogen desorption behavior on heterointerface, especially on the metal sulfides heterointerface, which severely restricts the alkaline Volmer and Heyrovsky reaction kinetics. Herein, we present a simple way to incorporate nitrogen into the NiS2/CoS2 heterostructure (N-NiS2/CoS2) to form an electron-reconfigured heterointerface. The electronic structure of active sites on N-NiS2/CoS2 interface can be effectively tuned by N dopant, thus realizing a promoted water adsorption and dissociation capability, and near-optimal hydrogen desorption behavior on N-NiS2/CoS2 interface. Consequently, the as-prepared N-NiS2/CoS2 heterointerface demonstrates an impressive HER performance with a low overpotential of 73 mV at the current density of 10 mA cm-2 and a small Tafel slope of 64.8 mV dec-1. This work sheds light on the strategies of element doping on interfacial engineering HER, and also provides valuable insights for rational design of a high-performance heterointerface electrocatalyst.