Design and Modulation of Oxygen Vacancy‐Rich Catalysts for Hydrogen and Oxygen Electrocatalysis in Energy Conversion

Oxygen vacancies (OVs) represent a powerful defect engineering strategy to overcome the sluggish kinetics of hydrogen/oxygen electrocatalytic reactions-the central bottleneck for sustainable energy conversion. This review systematically summarizes recent advances in the design, synthesis, and characterization of OV-rich metal oxide catalysts for the hydrogen evolution, hydrogen oxidation, oxygen evolution, and oxygen reduction reactions. We elucidate the fundamental mechanisms by which OVs enhance catalytic performance via modulating electronic structures, stabilizing crystal phases, accelerating ion migration, and optimizing surface intermediate adsorption. Key synthetic strategies and advanced characterization techniques are critically evaluated, with highlights on their applications in water splitting, ammonia borane hydrolysis, fuel cells, and metal-air batteries. Finally, we identify core challenges including precise OV spatial control, in situ dynamic characterization, and long-term catalyst stability, and provide perspectives for the rational design of high-performance OV-based electrocatalysts.