Design of an LSPR-driven hollow Cu2−xS@ZnIn2S4 heterojunction for synergistic photothermal-photocatalytic hydrogen evolution

To address the challenges of insufficient near-infrared light utilization and rapid charge recombination in traditional photocatalysts, this study designed and synthesized a hollow-structured Cu 2−x S@ZnIn 2 S 4 S-scheme heterojunction with synergistic photothermal-photocatalytic properties. The synergistic mechanism between plasmonic photothermal effects and heterojunction charge-transfer in broad-spectrum catalysis was systematically elucidated. Experimental results demonstrated that the composite achieved a hydrogen evolution rate of 32.58 mmol g −1  h −1 under AM 1.5G irradiation without cooling water (WCW), which is 3.00 times that of pure ZnIn 2 S 4 . Moreover, the solution temperature reached 47.4 °C under near-infrared (NIR) illumination. Theoretical analysis revealed that the localized surface plasmon resonance (LSPR) of Cu 2−x S extended light absorption into the NIR region and generated a photothermal effect. Meanwhile, the S-scheme band alignment, together with multiple light scattering induced by the hollow structure, synergistically optimized carrier separation and promoted directional charge migration. The catalyst exhibited excellent stability over 750 min and demonstrated measurable NIR-driven activity at wavelengths above 800 nm. By coupling band-engineering with photothermal conversion, this work provided a theoretical foundation and a material prototype for designing efficient full-spectrum solar-to‑hydrogen conversion systems, showing clear application potential in photothermal-assisted artificial photosynthesis.