Synergistic Coupling of Interfacial Oxidation Sites and S-Scheme Heterojunction in Cu₂WS₄@SnIn₄S₈ Core–Shell Nanocomposites Boosting CO₂ Photoreduction Efficiency

Photocatalytic CO2 reduction offers a dual solution to mitigate the energy crisis and reduce carbon emissions. In situ synthesis of the Cu2WS4@SnIn4S8 (CWS@SIS) composite has established S-S bonds at the interface, which act as atomic-scale interfacial "bridges" to stabilize the heterojunction interface. SnIn4S8 nanosheets are uniformly dispersed on the Cu2WS4 surface, activating the (101) crystal plane of Cu2WS4 to consume photogenerated holes. In addition, the S-scheme heterojunction facilitates efficient charge carrier separation and transfer. Under the synergistic effects of (101) plane activation and the S-scheme heterojunction, the CWS@SIS core-shell composite achieves photocatalytic CO2 reduction rates of 10.98 μmol·g-1·h-1 for CH4 and 3.85 μmol·g-1·h-1 for CO. This work proposes a novel strategy for advancing the design and application of core-shell S-scheme heterojunction photocatalysts.