Electrocatalytic water splitting over perovskite oxide catalysts

The urgent need for decarbonized hydrogen production to achieve carbon-neutral targets has highlighted the critical role of water electrolysis technology in advancing sustainability in various fields. However, the gap in economic efficiency between green hydrogen, generated by renewable electricity-driven water electrolysis, and gray hydrogen, generated by the consumption of fossil fuels, remains a challenge. Therefore, the exploration of cost-effective, active, and stable electrocatalysts toward water-splitting reactions is essential. Owing to their high-tolerance crystal structures, flexible elemental compositions, and adjustable electronic properties, perovskite oxides provide a vast material library for customizing next-generation electrocatalysts. Additionally, perovskite oxides are increasingly being developed into ideal model catalysts for unraveling scientific laws and theories, emphasizing the significance of investigating their important characteristics (e.g., structure-performance relationship, electronic property regulation, catalytic mechanism, and dynamic structural evolution). This review summarizes recent advances in perovskite oxides for water-splitting electrocatalysis, including their developmental history, compositional and structural diversities, structure-performance correlations, activity descriptors, catalytic mechanisms, and structural evolutions. We emphasize the importance of in situ characterization techniques for monitoring dynamic structural information and identifying important active species. Finally, we outline the opportunities and challenges of perovskite oxides for practical applications in water electrolysis, with the aim of providing further directions for exploring next-generation electrocatalysts.