ZnIn₂S₄/ZnO Film for High-Efficiency CO₂ Conversion to Fuel: Photocatalysis by Atomically Disorder-Engineered Heterointerface

Light-driven conversion of CO2 into small energy-rich molecules effectively addresses both energy demands and reduction in carbon dioxide emissions. However, due to the low efficiency of light absorption and charge carrier separation/transfer, most semiconducting materials have a low conversion activity and poor conversion product selectivity. Herein, ZnIn2S4 nanosheets are introduced to oxygen vacancy-rich ZnO microrod films for CO2 conversion. This heterostructure forms an atomically disordered heterointerface that can play an important role in strengthening the contact between the two crystalline materials and providing an efficient charge transfer pathway. The resulting ZnIn2S4/ZnO film photocatalyst exhibits superior performance compared to other ZnO-film-based photocatalysts (0.84 and 0.34 μmol·cm-2·h-1 for CH4 and CO, respectively) with ∼90.8% selectivity toward CH4 production. The formation of the ZnIn2S4/ZnO heterojunction film contributes to strengthening the charge carrier generation, separation, and migration through a defect-engineered Z-scheme mechanism. This work highlights the role of disorder-engineered heterointerfaces in film-based heterostructured photocatalysts for optimizing the CO2 conversion efficiency.