Sulfur‐Deficient ZnIn₂S₄/Oxygen‐Deficient WO₃ Hybrids with Carbon Layer Bridges as a Novel Photothermal/Photocatalytic Integrated System for Z‐Scheme Overall Water Splitting

Abstract Although photocatalytic overall water splitting is a potential technology for converting solar energy into chemical fuel, the widely reported solar‐to‐hydrogen efficiency is around 1%, indicating unsatisfactory photocatalytic performance. Here, a novel photocatalyst material is designed and a whole reaction system is constructed, resulting in an integrative photothermal–photocatalytic Z‐scheme overall water splitting reaction system. In terms of materials design, a novel sulfur‐deficient ZnIn 2 S 4 /oxygen‐deficient WO 3 (ZIS–WO) hybrid with surface‐carbonized wood (C‐wood) is reported. The ZIS–WO hybrid with sulfur and oxygen vacancies promotes the adsorption of visible light and the separation of charge carriers. The conductive C‐wood is strategically used as an additional electron bridge to accelerate electron transfer. In terms of system construction, the C‐wood exploits the photothermal effect to change the solid/liquid/gas triphase system to a solid/gas biphase system by transforming liquid water into steam, which drastically restrains carrier recombination, and decreases the photocatalytic reaction barrier. The H 2 and O 2 production rates in the proposed system are approximately 169.2 and 82.5 µmol h –1 under air mass (AM) 1.5 light irradiation, and the corresponding solar‐to‐hydrogen efficiency is as high as 1.52%. The study from photocatalyst design to reaction system construct opens a new insight for versatile and high‐performance photocatalytic overall water splitting.