Light-induced CoO_X surface reconstruction in hollow heterostructure for durable photocatalytic seawater splitting

Photocorrosion triggered by the unconsumed photogenerated holes severely deteriorates the photocatalytic efficiency and stability of semiconductor photocatalysts, especially in seawater with complex ions. Here, we report a hierarchical hollow ZnIn₂S₄ heterostructure integrating an inner CoO_x nanocage and atomically dispersed Pt anchoring at surface S vacancies for hydrogen evolution from natural seawater (23.88 mmol g^-1 h^-1) and pure water (48.99 mmol g^-1 h^-1) under visible light. The dynamic Co²⁺/Co³⁺ self-reconstruction of the inner CoOx cage effectively consumes photogenerated holes, while the outer Pt₁ single atoms localized at S vacancies serve as electron sinks to facilitate electron extraction and proton reduction. Benefiting from the dynamic hole-scavenging mechanism via oxidation self-reconstruction, the Pt₁-ZnIn₂S₄@CoO_X photocatalyst exhibits enhanced durability against alkali metal ions in seawater and maintains high reactivity for long-term hydrogen evolution. This work underscores the importance of light-induced transition metal dynamic self-reconstruction within hierarchical hollow heterostructure photocatalysts for sustainable hydrogen evolution.