0D/3D heterostructure of perovskite Cs2CuBr4 quantum dots/Bi2O3 microflower as a step-scheme photocatalyst for enhanced CO2 reduction

Exploring highly-efficient photocatalytic materials to convert CO2 into clean energy fuels is of great significance. Herein, lead-free perovskite Cs2CuBr4 quantum dots (QDs) were loaded onto Bi2O3 microflower to construct a 0D/3D heterostructure of Cs2CuBr4/Bi2O3 (CCB/Bi2O3) for photocatalytic CO2 reduction reaction (CO2 RR). The developed 0D/3D CCB/Bi2O3 heterostructure exhibited dramatically enhanced CO2 RR activity, with an electron consumption rate (Relectron) up to 322.12 μmol g−1 h−1, which was 3.16 folds that of pure Cs2CuBr4 QDs. The improvement of CO2 RR activity was originated from the promoted carrier separation and transfer, as well as retainment of strongly reducing electrons induced by the step-scheme electron transfer mode, as authenticated by in-situ X-ray photoelectron spectra (XPS), electron paramagnetic resonance (EPR), and density function theory (DFT) calculation. The CO2 RR pathway was unveiled by in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The innovation of perovskite QDs-based step-scheme heterostructures can throw inspiration on designing high-performance photocatalysts applied in artificial photosynthesis.