Interface engineering of hollow Janus-structured NiCoP/P-MoS₂ heterojunction as self-supported electrode enables boosted alkaline hydrogen evolution reaction

Transition metal phosphorus (TMPs) and sulfides have attracted extensive attention as important candidates to replace noble metal-based hydrogen evolution (HER) catalysts. However, the insufficient specific surface area, low conductivity and easy detachments from electrode seriously affect the HER catalytic activity and stability. Herein, a novel self-supported hollow Janus-structured NiCoP/P-MoS₂ heterojunction is designed on carbon cloth (CC) as high-performance electrocatalyst for alkaline HER. The binder-free NiCoP/P-MoS₂/CC electrode with well-dispersed hollow structure exhibits acceptable durability and low overpotential, which requires overpotential of 52.6 mV to reach 10 mA cm⁻², far superior to that of NiCoP/CC (111.2 mV), P-MoS₂/CC (213.3 mV) electrode and also the corresponding NiCoP/P-MoS₂ powder catalyst (113.1 mV). Experimental and theoretical results confirm that heterointerface interaction can improve the electronic state, accelerate charge transfer and optimize hydrogen adsorption energy, resulting in boosted HER kinetic process. Additionally, self-supported strategy is conducive to tightly anchoring high-quality active substances with well-organized hollow array structure, which significantly prevents the catalyst agglomeration and shedding, leading to the improved HER stability. This work offers valuable insights into the catalytic mechanisms and provides an avenue for designing hierarchical architecture for highly efficient and stable HER electrocatalysts.