Hollow ZnCdS/CuInS₂ S‑Scheme Heterojunction for Superior Photothermal-Assisted Photocatalytic Coupled H₂O₂ and...

Photocatalytic H₂O₂ production coupled with selective oxidation of benzyl alcohol represents a highly attractive yet challenging "one-stone-two-birds" strategy for sustainable chemical synthesis. The major obstacles lie in the difficulty of synchronizing spatial charge separation, preserving high redox potentials, and precisely steering the reaction pathways. Herein, a novel hollow ZnCdS/CuInS₂ S-scheme heterojunction is constructed through solid-solution band engineering. This multifunctional design integrates three synergistic effects to break the above limitations: (i) rapid charge separation driven by S-scheme heterojunction while retaining strong redox capability; (ii) broad-band light harvesting and photothermal effect facilitated by hollow nanobox architecture; (iii) ideal reaction kinetics and thermodynamics optimized by photothermal temperature rise. The developed catalyst achieves remarkable co-production rates under full-spectrum irradiation: 3052.5 µmol g^-1 h^-1 for H₂O₂ and 5211.6 µmol g^-1 h^-1 for benzaldehyde, with nearly 100% selectivity for benzaldehyde. It is unraveled that the photothermal-induced moderate local heating triggers a controllable homolysis of H₂O₂, generating a favorable concentration of hydroxyl radicals. This process enables precise activation of the C─H bonds in benzyl alcohol while suppressing unwanted over-oxidation pathways. This work establishes a paradigm for advanced photocatalytic coupling systems, where charge-separation engineering and photothermal-microenvironment regulation act in concert to promote efficient and selective solar-to-chemical conversions.