Ru-anchored heterojunction catalyst: synergistic modulation of electronic structure for efficient hydrogen evolution reaction

Proton exchange membrane water electrolysis (PEMWE) is a key hub connecting renewable energy to green hydrogen, but its cathode hydrogen evolution reaction (HER) still heavily relies on high-cost platinum. To address this, a novel heterojunction catalyst was successfully designed and constructed, with Ru nanoparticles as the active centers and a MoS₂/MoO₂/graphene triphase heterojunction as the regulator (Ru@MoS₂/MoO₂/Gr), achieved through a reduction-annealing strategy. Here, Gr serves as a conductive skeleton, MoS₂ provides abundant edge active sites and is induced to generate S vacancies, while in situ formed MoO₂ during heat treatment possesses metal-like high conductivity. Strong metal–support interaction (SMSI) facilitates electron transfer from MoS₂ to Ru, synergistically optimizing the adsorption energy of hydrogen intermediates. Electrochemical tests show that the prepared catalyst exhibits excellent HER activity and stability in acidic, alkaline, and neutral electrolytes. In a practical PEMWE test, the membrane electrode assembled with this catalyst achieved a current density of 1000 mA cm⁻² at only 2.08 V and operated stably for 250 h. This study provides new ideas for designing universal, high-performance water electrolysis catalysts suitable for complex operating conditions.