Mesoporous α‑Fe2O3 nanostructures decorated with perovskite Cs3Bi2Br9 quantum dots as an S-scheme photocatalyst for efficient charge transfer and CO2 conversion

Abstract

In view of the greenhouse effect caused by excessive CO2 emission in the atmosphere, the efficient capture and conversion of CO2 to chemical feedstock is imminent. Herein, a novel Cs3Bi2Br9/α‑Fe2O3 (CBB/α‑Fe2O3) composite was constructed by decorating lead-free perovskite Cs3Bi2Br9 quantum dots (QDs) on the pores of mesoporous α‑Fe2O3 nanostructures. The developed CBB/α‑Fe2O3 composite possesses bifunctional advantages for both the efficient capture and conversion of CO2, with a CO production yield of 84.12 μmol g−1h−1 for the optimized sample. Experimental results and theoretical predictions indicate that the electrons transfer via an S-scheme route in the CBB/α‑Fe2O3 composite, which not only boosts the charge separation but also retains the strong reduction ability of Cs3Bi2Br9. By combination of in-situ diffuse reflectance infrared Fourier transform spectra (DRIFTS) with theoretical calculations, the mechanism of the photocatalytic CO2 reduction over the CBB/α‑Fe2O3 composite was explored in depth. This study opens a new avenue for the exploitation of photocatalysts with high CO2 capture ability and conversion efficiency.