Boosting Hydrogen Evolution Reaction Performance of Oxygen Vacancies-Rich Moo2/Comoo4 Heterojunction Via Regulating the Electron Distribution of Mo-O

Abstract

Developing efficient non-platinum electrocatalysts for hydrogen evolution reaction (HER) in alkaline electrolyte remains a significant challenge. Herein, we constructed oxygen vacancies-rich MoO2@CoMoO4 (MCO@NF) nanorods heterojunction catalyst for HER in alkaline medium. The rich oxygen vacancy could regulate the coordination of Mo sites and optimize electronic structure, which endowed the heterojunction electrocatalyst excellent electrical conductivity. The heterojunction structure facilitated the electrons redistribution at interface and increased Mo6+ content of MCO@NF. Importantly, the Mo6+-O exhibited high stability, which could enhance the durability of MCO@NF. Moreover, the Mo6+ ions in the Mo-O structure stimulated the migration of electrons from Mo to the O, and the O with high electron density could optimize the hydrogen adsorption energy of O sites, which was conducive to HER electrocatalytic activity. Thus, the MCO@NF exhibited a low overpotential of 31 mV at 10 mA cm−2 and the overpotential at current density of 100 mA cm−2 hardly changed after 100 h durability test. This work is of great significance for creation of efficient HER electrocatalysts by using the synergistic effect between the heterojunction and oxygen vacancies.

Keywords: Hydrogen evolution reactions, MoO2@CoMoO4 heterojunction, Electronic regulation, Long-term durability