Boosting hydrogen evolution via work-function-accelerated electronic reconfiguration of Mo-based heterojunction

Abstract

Molybdenum-based catalysts have demonstrated significant potential in the electrocatalytic hydrogen evolution reaction (HER). However, the limited exposure of active sites and strong hydrogen adsorption result in suboptimal performance. Herein, a Mo₂N–MoSe₂ heterojunction is prepared on carbon cloth (MNS/CC) to enhance the HER. The strong electronic interaction between Mo₂N and MoSe₂, combined with the lower work function of Mo₂N, creates an intrinsic electric field at the heterojunction interface, which markedly improves charge transfer efficiency. Additionally, the optimized electronic structure of Mo sites further enhances charge transfer and intrinsically catalytic activity in HER. As a result, MNS/CC requires overpotentials of mere 65 and 210 mV to achieve current densities of 20 mA cm⁻² and 1 A cm⁻², respectively, with a Tafel slope of only 96 mV dec⁻¹. Moreover, MNS/CC maintains stable operation at 1 A cm⁻² for 240 h without significant degradation. The results offer insights into the design of non-precious metal-based electro-catalysts for industrial hydrogen production.