Advances in Oxygen Vacancy‐Driven Hydrogen Production via Water Electrolysis

ABSTRACT Oxygen vacancy (O v ), as a central strategy in defect engineering, plays a pivotal regulatory role in hydrogen production via water electrolysis. This review systematically addresses the scientific understanding of O v in the hydrogen evolution reaction (HER). First, the relationship between the spatial distribution of O v and the intrinsic mechanisms that enhance catalytic activity is summarized, along with the hydrogen production pathways on O v ‐containing catalysts. Second, the principles of O v construction strategies and their impacts on structural stability, defect density, and overall catalytic performance are comprehensively examined. Third, a series of complementary characterization techniques for O v are elaborated, which lays a solid experimental foundation for verifying the existence of O v , quantifying its concentration, and establishing structure–activity relationships. Fourth, the superior performance of O v ‐modified catalysts in HER has been analyzed. The catalytic effects produced by different mechanisms were quantitatively described through measurable indicators. This review establishes connections among O v characteristics, preparation strategies, characterization techniques, reaction pathways, and HER catalytic performance, thereby enhancing the potential for applying O v strategies in the efficient, large‐scale hydrogen production.