New insights into the enhancement of TiO2/ZnIn2S4 heterojunction via cerium doping

S-scheme heterojunction photocatalysts are promising for practical application as their high efficiency in the generation and separation of photogenerated charges. In this work, simple Ce doping was utilized to modify TiO2/ZnIn2S4, a TiO2-based S-scheme heterojunction. The Ce-TiO2/ZnIn2S4 sample with 10 wt% ZnIn2S4 supported and 5 at.% Ce doping possessed excellent photocatalytic activity and reusability. Compared with other heterojunction photocatalysts presented in previous studies, the optimal Ce-TiO2/ZnIn2S4 showed delightful photocatalytic reduction activity. Combining DFT calculation, the shift of binding energies, electrochemical tests and quantitative built-in electric field (IEF) intensity, it was confirmed that low-electronegativity Ce doping could improve the IEF intensity at TiO2/ZnIn2S4 interface, resulting in an outstanding separation efficiency of photogenerated charges. This work proposes an ordinary but effective technology to facilitate the interface transference of photogenerated charges.