Advances in Oxygen Vacancy-Driven Hydrogen Production via Water Electrolysis.

Oxygen vacancy (Ov), 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 Ov in the hydrogen evolution reaction (HER). First, the relationship between the spatial distribution of Ov and the intrinsic mechanisms that enhance catalytic activity is summarized, along with the hydrogen production pathways on Ov-containing catalysts. Second, the principles of Ov 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 Ov are elaborated, which lays a solid experimental foundation for verifying the existence of Ov, quantifying its concentration, and establishing structure-activity relationships. Fourth, the superior performance of Ov-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 Ov characteristics, preparation strategies, characterization techniques, reaction pathways, and HER catalytic performance, thereby enhancing the potential for applying Ov strategies in the efficient, large-scale hydrogen production.