Perovskite oxides as electrocatalysts for water electrolysis: From crystalline to amorphous

Crystalline perovskite oxides are regarded as promising electrocatalysts for water electrolysis, particularly for anodic oxygen evolution reactions, owing to their low cost and high intrinsic activity. Perovskite oxides with noncrystalline or amorphous characteristics also exhibit promising electrocatalytic performance toward electrochemical water splitting. In this review, a fundamental understanding of the characteristics and advantages of crystalline, noncrystalline, and amorphous perovskite oxides is presented. Subsequently, recent progress in the development of advanced electrocatalysts for water electrolysis by engineering and breaking the crystallinity of perovskite oxides is reviewed, with a special focus on the underlying structure–activity relationships. Finally, the remaining challenges and unsolved issues are presented, and an outlook is briefly proposed for the future exploration of next-generation water-splitting electrocatalysts based on perovskite oxides.