Interfacial hydrogen spillover and coherent lattice matching in ZnIn2S4/ZnCo2S4 enable synchronized electron-proton delivery for efficient photocatalytic H2 evolution

• • Achieved an atomically coherent heterointerface with an ultralow lattice mismatch of 0.05%, suppressing trap-mediated recombination and enabling efficient interfacial charge transfer, which is critical for high-performance heterojunction photocatalysts. • • Demonstrated synchronized electron-proton delivery via hydrogen spillover, yielding a photocatalytic H2 evolution rate of 70.3 mmol g−1 h−1, significantly outperforming conventional systems and addressing the bottleneck of asynchronous charge supply. • • Achieved selective oxidation of benzyl alcohol to aldehyde with a rate of 39.3 mmol g−1 h−1 and 93.6% selectivity, showcasing dual functionality for simultaneous H2 production and value-added chemical synthesis. • • Established that lattice matching and dual charge-proton management are essential design principles for efficient PCET, providing a roadmap for developing next-generation photocatalysts for solar-to-chemical energy conversion.