Ru-Anchored Heterojunction Catalyst: Synergistic Modulation of Electronic Structure for Efficient Hydrogen Evolution Reaction

Abstract

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.