Strain‐Engineering of Mesoporous Cs<sub>3</sub>Bi<sub>2</sub>Br<sub>9</sub>/BiVO<sub>4</sub> S‐Scheme Heterojunction for Efficient CO<sub>2</sub> Photoreduction
Biao Zhou, Shuang Xu, Liqin Wu, Mingjie Li, Yanan Chong, Yongcai Qiu, Guangxu Chen, Yun Zhao, Chunhua Feng, Daiqi Ye, Keyou Yan
Abstract
Abstract Slow charge kinetics and unfavorable CO 2 adsorption/activation strongly inhibit CO 2 photoreduction. In this study, a strain‐engineered Cs 3 Bi 2 Br 9 /hierarchically porous BiVO 4 (s‐CBB/HP‐BVO) heterojunction with improved charge separation and tailored CO 2 adsorption/activation capability is developed. Density functional theory calculations suggest that the presence of tensile strain in Cs 3 Bi 2 Br 9 can significantly downshift the p‐band center of the active Bi atoms, which enhances the adsorption/activation of inert CO 2 . Meanwhile, in situ irradiation X‐ray photoelectron spectroscopy and electron spin resonance confirm that efficient charge transfer occurs in s‐CBB/HP‐BVO following an S‐scheme with built‐in electric field acceleration. Therefore, the well‐designed s‐CBB/HP‐BVO heterojunction exhibits a boosted photocatalytic activity, with a total electron consumption rate of 70.63 µmol g −1 h −1 , and 79.66% selectivity of CO production. Additionally, in situ diffuse reflectance infrared Fourier transform spectroscopy reveals that CO 2 photoreduction undergoes a formaldehyde‐mediated reaction process. This work provides insight into strain engineering to improve the photocatalytic performance of halide perovskite.