Hexagonal Defect-Rich MnOx/RuO2 with Abundant Heterointerface to Modulate Electronic Structure for Acidic Oxygen Evolution Reaction

Developing green hydrogen energy to power future societies has driven the progress of proton-exchange membrane water electrolyzers (PEMWE). However, due to the complex anode oxygen evolution reaction (OER) electron transfer process and the strong acidic environment, the most effective catalysts are still Ir-based nanomaterials. Therefore, exploiting low cost acidic OER catalysts to meet the needs of PEMWE remains a challenging and rewarding task. Herein, hexagonal-shaped and defect-rich MnOx/RuO2 heterojunction nanosheets (H/d-MnOx/RuO2) is designed. The oxygen vacancies and heterogeneous structure enable the H/d-MnOx/RuO2 catalyst to reach 10 mA cm(-2) with only overpotential 178 mV in 0.5 m H2SO4. Density functional theory shows that the oxygen vacancies and heterogeneous interface facilitates the reduction of the adsorption energy of *OOH and the reduction of the energy level of Ru-Oads, thus suppressing the involvement of lattice oxygen and enhancing the durability. This study provides an effective way to design efficient catalysts for hydrogen production in PEMWE.