Boosting Carrier Separation on a BiOBr/Bi<sub>4</sub>O<sub>5</sub>Br<sub>2</sub> Direct Z-Scheme Heterojunction for Superior Photocatalytic Nitrogen Fixation
Huiqing Wang, Zhuohua Chen, Yaru Shang, Chade Lv, Xuhan Zhang, Fei Li, Qunzeng Huang, Xiaodi Liu, Wenmin Liu, Liang Zhao, Liqun Ye, Haiquan Xie, Xiaoli Jin
Abstract
Photocatalytic dinitrogen (N 2 ) fixation is regarded as an achievable technology for ammonia (NH 3 ) production. However, the poor separation efficiency of the photoinduced carriers and ineffective N 2 activation remain grand obstacles to high-performance NH 3 photosynthesis. Designing advanced heterostructured systems to accelerate charge separation and activate the N 2 molecule is a feasible strategy to optimize the photocatalytic N 2 fixation activity. Herein, a direct Z-scheme configuration is established between BiOBr and Bi 4 O 5 Br 2 through a facile one-step solvothermal reaction. This configuration enables effective spatial separation of electron–hole pairs and preserves the robust redox ability of carriers, concurrently promoting N≡N bond activation and diminishing the energy barrier for the rate-determining step. The formation of direct Z-scheme BiOBr/Bi 4 O 5 Br 2 heterojunctions is mostly attributed to the similarities in their lattice structures and crystal growth conditions. As a result, the direct Z-scheme BiOBr/Bi 4 O 5 Br 2 heterojunction exhibits a high NH 3 yield of 66.87 μmol g –1 h –1 without using sacrificing reagents, surpassing that of the pristine BiOBr and Bi 4 O 5 Br 2 by approximately 3.3 and 5.6 times, respectively. This study provides an achievable approach to construct direct Z-scheme heterojunction systems for implementing high-performance N 2 fixation under mild conditions.