Beyond static paradigms: defect dynamic evolution and advanced applications in water electrolysis.

Electrocatalytic reactions play crucial roles in energy conversion and green chemical synthesis; however, their practical applications are often constrained by sluggish reaction kinetics, high overpotentials, and insufficient operational stability. In recent years, defect engineering has emerged as an effective structural regulation strategy, providing new opportunities to enhance electrocatalytic performance through the deliberate introduction of non-ideal structural features, such as vacancies, heteroatom dopants and interfacial architectures. Accumulating studies have demonstrated that defects not only modulate the electronic structure of catalysts and reaction pathways, but that their dynamic evolution under specific reaction conditions also exerts profound influence on the real working-state structure and long-term catalytic performance. Owing to central importance in green hydrogen production, water-splitting reactions serve as representative model systems for elucidating defect-structure-activity relationships. In this review, we systematically summarize recent advances in defect engineering for electrocatalysis, with particular focus on water electrolysis. Emphasis is placed on defect types and structural characteristics, construction strategies, dynamic evolution behaviors, and their typical applications, while current challenges and future research directions are also discussed, aiming to provide valuable guidance for the rational design and practical implementation of high-performance defect-engineered electrocatalysts.