Surface Ce single atoms and S-vacancies synergically enhanced photoreduction of CO2 over Ce-ZnIn2S4 nanosheets

The rare intrinsic active sites and low charge transfer capabilities of catalysts cause the unsatisfied selectivity and activity in photocatalytic reduction of CO₂. Utilizing single atoms doping into a catalyst to overcome these issues for improving the catalytic performance may be a highly desirable and challenging endeavor. Herein, single atoms Ce doped ZnIn₂S₄ (ZIS) nanosheets were prepared as photocatalysts for the reduction of CO₂ under visible light, achieving efficient syngas production of 19.8 mmol g⁻¹h⁻¹, with an adjustable CO/H₂ ratios from 1:4 to 1:1. Characterizations results reveal that Ce single atoms sites are dispersed on the surface of ZIS, forming the abundant S-vacancies via the lattice distortion of ZIS. These Ce single atoms sites and S-vacancies (Sv) can greatly enhance the separation and transport efficiency of photogenerated carriers. Density functional theory calculations and experiment results exhibit that electrons-rich Ce atoms can selectively absorb and reduce CO₂, while Sv serve as the active sites for the reduction of H₂O. This work offers a unique horizon for constructing single-atom doped catalysts and understanding the synergistic catalytic pathway of surface metal single atoms and vacancies.