Built-In Electric Field-Promoted Perovskite p–n Heterojunction for Efficient and Selective CO2 Photocatalysis
Jiong Li, Binyan Zou, Xianghai Rao, Yixiang Li, Wenjia Zhou, Xiangdong Shi, Tao Wang, Zhiheng Li, Bingkun Liu, Jianbo Zhao, Chenghao Duan, Fenghua ChenAbstract
Rapid charge carrier recombination and limited charge transport constrain the efficiency of semiconductor-based CO2 photoreduction. To address both limitations, p-type Cu2O was coupled with n-type Cs2AgBiBr6 (CABB) to construct a p–n heterojunction, in which the interfacial built-in electric field facilitates charge separation and directional carrier migration. Under simulated solar irradiation, 10 wt % Cu2O/CABB achieved a CO production rate of 27.51 μmol·g–1·h–1 and a CO selectivity of 83.07%. The CO production rate was 2.53 and 3.85 times the rates obtained over pristine Cu2O and CABB, respectively. The study demonstrates how a p–n heterojunction, together with the associated built-in electric field, enhances photogenerated carrier separation and photocatalytic CO2 reduction, while introducing a new approach to developing and optimizing photocatalytic materials with high selectivity.