The Formation of Unsaturated IrOx in SrIrO3-based Perovskites by Cobalt-doping for Efficient Acidic Oxygen Evolution Reaction

Abstract Electrocatalytic water splitting is a promising route for sustainable hydrogen production. However, the high overpotential of the anodic oxygen evolution reaction (OER) poses significant challenge. SrIrO3-based perovskite-type catalysts have shown great potential for OER in acidic medium, but the origins of their high activity are still unclear. Herein, we develop a Co-doped SrIrO3 system to enhance OER activity and elucidate the origin of catalytic activity. In-situ experiments reveal Co activates surface oxygen, rapidly exposing IrOx active sites, while bulk Co doping optimizes the adsorbate binding energy of IrOx. The Co-doped SrIrO3 demonstrates excellent OER electrocatalytic activity, markedly surpassing the commercial IrO2 catalysts in both conventional electrolyzer and proton exchange membrane water electrolyzer. The insights significantly advance the understanding of how SrIrO3-based perovskites achieve high acidic OER catalytic performance. The findings also provide guidance for designing efficient acidic OER electrocatalysts toward green hydrogen production.