Applications of perovskite oxides for oxygen evolution and oxygen reduction reactions in alkaline media

It is urgent to develop novel energy storage and conversion systems to address the pressing issues of the energy crisis and environmental pollution, including alkaline water electrolysis, alkaline fuel cells and metal-air batteries. However, these systems are hampered by the sluggish kinetics of the oxygen evolution reaction (OER) or oxygen reduction reaction (ORR). One of the most effective strategies to overcome this challenge is the development of efficient and stable catalysts for both ORR and OER, which typically consist of Pt, Ir, or other precious metals. Unfortunately, most precious metal catalysts are limited to single catalytic activity (either ORR or OER) and are constrained by the high cost and scarcity of noble metals. Perovskite oxides offer significant promise as efficient bifunctional ORR/OER catalysts due to their high catalytic activity, versatile composition, low cost, and high stability in alkaline environments. The general preparation methods of perovskite-type oxides are summarized in this work. Then recent mechanistic studies on the ORR and OER of perovskite oxides are also discussed, particularly highlighting the theoretical and experimental methods employed to facilitate these studies. Further strategies for improving the catalytic performance of perovskite oxides are discussed from five perspectives. The perspective of challenges and future directions for the development of perovskite oxides in ORR and OER applications are finally presented. Graphical Abstracts.