Highly Efficient Perovskite‐Based Electrocatalysts for Water Oxidation in Acidic Environments: A Mini Review

Proton‐conducting polymer electrolyte membrane water electrolysis (PEMWE) is a promising technology for generating clean and sustainable hydrogen fuels from water. However, PEMWE requires the use of expensive electrocatalysts; the currently available electrocatalysts for the oxygen evolution reaction (OER) depend on noble metals (Ir, Ru). Since noble metals are expensive, commercialization of PEMWE remains elusive. In addition, PEMWE suffers from the very slow kinetics of the OER in acidic media. Thus, the development of noble‐metal‐reduced, highly active, and acid‐compatible oxygen evolution electrocatalysts is needed for the commercialization of PEMWE to be viable. In this regard, perovskite oxides have great potential for application as OER electrocatalysts in acidic media, because their multimetal‐oxide forms can reduce the use of noble metals, and their high structural and compositional flexibility can modulate the electronic structure and OER activity. In this review, current knowledge regarding state‐of‐the‐art perovskite oxides for acidic water oxidation electrocatalysts is summarized. First, the fundamental OER mechanism of electrocatalysts in acidic media is introduced briefly. Second, Ir‐ and Ru‐based perovskite oxides in acidic solutions are provided, focusing on their stability and OER activity. Finally, some challenges facing the development of perovskite oxide‐based electrocatalysts, and a perspective on their future are discussed. Recent developments and advances in state‐of‐the‐art perovskite oxides for efficient acidic water oxidation electrocatalysts are highlighted. Due to the fact that perovskite oxides are prone to dissolution in acidic environments, the stability or possible changes of perovskite oxide electrocatalysts after oxygen evolution reaction tests are discussed, and their oxygen evolution reaction activity and reaction mechanism are also introduced.