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.

Given the rapid recombination of photogenerated charge carriers and photocorrosion, transition metal sulfide photocatalysts usually suffer from modest photocatalytic performance. Herein, S-vacancy-rich ZnIn₂S₄ (V_S-ZIS) nanosheets are integrated on 3D bicontinuous nitrogen-doped nanoporous graphene (N-npG), forming 3D heterostructures with well-fitted geometric configuration (V_S-ZIS/N-npG) for highly efficient photocatalytic hydrogen production. The V_S-ZIS/N-npG presents ultrafast interfacial photogenerated electrons captured by the S vacancies in V_S-ZIS and holes neutralization behaviors by the extra free electrons in N-npG during photocatalysis, which are demonstrated by in situ XPS, femtosecond transient absorption (fs-TA) spectroscopy, and transient-state surface photovoltage (TS-SPV) spectra. The simulated interfacial charge rearrangement behaviors from DFT calculations also verify the separation tendency of photogenerated charge carriers. Thus, the optimized V_S-ZIS/N-npG 3D hierarchical heterojunction with 1.0 wt % N-npG exhibits a comparably high hydrogen generation rate of 4222.4 μmol g^-1 h^-1, which is 5.6-fold higher than the bare V_S-ZIS and 12.7-fold higher than the ZIS without S vacancies. This work sheds light on the rational design of photogenerated carrier transfer paths to facilitate charge separation and provides further hints for the design of hierarchical heterostructure photocatalysts.