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

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.