Interfacial Engineering of S-Scheme WO3/In2S3 Heterojunction for Efficient Solar-Driven CO2 Photoreduction

CO2 photoreduction technology offers significant potential for addressing energy and environmental challenges, though its practical application is hindered by insufficient photo-absorption and rapid carrier recombination. Herein, we constructed the WO3/In2S3 S-scheme heterojunction through hydrothermal assembly of two-dimensional WO3 nanosheets and scale-like In2S3 nanoflakes. Systematic characterization via XRD, XPS, SEM, and TEM verified the successful preparation of hierarchical nanostructures with optimized interfacial contact in the WO3/In2S3 composites. UV-Vis DRS analysis showed that the photo-absorption range of the catalyst was significantly widened. Photoelectrochemical investigations (EIS, TPR, PL, and LSV) revealed enhanced carrier separation efficiency and reduced recombination kinetics in the heterojunction system. The optimized WO3/In2S3 (WI-60) catalyst had a CO evolution efficiency of 55.14 μmol·g−1 under the UV-Vis light, representing a 3.9-fold enhancement over the pure In2S3 (14.08 μmol·g−1). Mechanistic studies through the XPS and band-structure analysis confirmed the establishment of an S-scheme carrier’ transfer pathway, which simultaneously preserved strong redox potentials and promoted the separation process of carriers. This research provides a validated strategy for developing efficient S-scheme photocatalytic systems for solar fuel generation.