Breaking the Ru−O−Ru Symmetry of a RuO₂ Catalyst for Sustainable Acidic Water Oxidation

Proton exchange membrane water electrolysis is a highly promising hydrogen production technique for sustainable energy supply, however, achieving a highly active and durable catalyst for acidic water oxidation still remains a formidable challenge. Herein, we propose a local microenvironment regulation strategy for precisely tuning In-RuO₂ /graphene (In-RuO₂ /G) catalyst with intrinsic electrochemical activity and stability to boost acidic water oxidation. The In-RuO₂ /G displays robust acid oxygen evolution reaction performance with a mass activity of 671 A gcat ⁻¹ at 1.5 V, an overpotential of 187 mV at 10 mA cm⁻² , and long-lasting stability of 350 h at 100 mA cm⁻² , which arises from the asymmetric Ru-O-In local structure interactions. Further, it is unraveled theoretically that the asymmetric Ru-O-In structure breaks the thermodynamic activity limit of the traditional adsorption evolution mechanism which significantly weakens the formation energy barrier of OOH*, thus inducing a new rate-determining step of OH* absorption. Therefore, this strategy showcases the immense potential for constructing high-performance acidic catalysts for water electrolyzers.