Space-Confined Growth of Cs2CuBr4 Perovskite Nanodots in Mesoporous CeO2 for Photocatalytic CO2 Reduction: Structure Regulation and Built-in Electric Field Construction

Halide perovskites have shown great promise in photocatalyticCO(2) conversion. However, their practical application isseriouslyhindered by severe charge recombination and inadequate adsorption/activationtoward CO2 molecules. Herein, the space-confined growthof lead-free Cs2CuBr4 perovskite nanodots inmesoporous CeO2 was realized by a facile impregnation approach.An outstanding CO2 photoreduction performance is achievedby the optimum Cs2CuBr4/CeO2 heterojunctionwith CO and CH4 yields of 271.56 and 83.28 mu mol g(-1), respectively. Experimental characterizations andtheoretical calculations cooperatively validate the S-scheme chargetransfer mechanism in the Cs2CuBr4/CeO2 heterojunction. The CO2 photoreduction pathway is alsorevealed by combining in situ diffuse reflectance infrared Fouriertransform spectra (DRIFTS) and density functional theory (DFT) calculations.This study provides useful guidance for the design of high-performancehalide perovskite/mesoporous material heterostructure photocatalystsfor artificial photosynthesis.