A MOFs-derived heterostructure electrocatalyst for acidic oxygen evolution with low degradation rate

Abstract Developing efficient and stable oxygen evolution reaction (OER) electrocatalysts that can work stably in acidic conditions is crucial for advancing proton-exchange membrane water electrolysers commercialization. Here, we prepared a heterostructure-based OER electrocatalyst by in-situ growing RuO2 nanoparticles on metal-organic-framework-derived Co3O4 nanoaggregates that can operate stably in acidic electrolytes. The interface of RuO2/Co3O4 heterostructure, as well as their effect on electronic structure, were examined by various advanced characterizations. The optimized RuO2/Co3O4 electrocatalyst reveals an ultra-low overpotential of 206 and 320 mV at 10 and 100 mA·cm−2, respectively. X-ray photoelectron spectroscopy, differential electrochemical mass spectroscopy measurements and theoretical calculations indicate that the as-constructed RuO2/Co3O4 interfaces could reduce the metal-oxygen covalence and energy barriers of rate-determining step, thereby decreasing the participation of lattice oxygen and preventing excessive oxidation of Ru sites during OER. In practical PEMWE systems, RuO2/Co3O4 achieves 1.63 V at 1 A·cm−2, and maintains remarkable stability for over 500 h with a very small voltage degradation rate of 0.2 mV·h−1. This study provides a promising avenue for developing cost-effective OER electrocatalysts with superior activity and stability for advanced energy conversion.