Fabrication of Ce-doped UiO-66-NH2 for highly efficient and selective photocatalytic reduction of CO2 to CH4

Defect engineering by creating oxygen vacancies (OVs) and heterogeneous frustrated Lewis acid-base pairs (FLPs) emerged as an efficient strategy to enhance the selective conversion CO 2 to CH 4 . Considering the intrinsic FLPs contained in UiO-66-NH 2 (UNH for abbreviation), in this paper, the OVs was introduced therein by fabricating the Ce-doped UNH (denoted as UNH(Ce/Zr)) via one-step solvothermal route. The as-prepared UNH(Ce/Zr) catalyst exhibited the CH 4 yield of 31.02 μmol·g −1 ·h −1 accompanied with the CH 4 selectivity of 93 % and satisfying recycling stability. The XRD, SEM, FT-IR, XPS, TG, TPD and NH 3 in situ DRIFTS and in situ FT-IR characterization results justified that the UNH(Ce/Zr) possess the obviously increased OVs sites and enhanced Lewis acidic and basic properties. Additionally, the photoelectrochemical characterization results showed that UNH(Ce/Zr)−0.014 efficiently improved photogenerated electron-hole separation efficiency and charge transfer rate. It could be concluded that it was the cooperative action of OVs and FLPs that led to the high CH 4 selectivity and CH 4 yield.