Oxygen and Nitrogen Vacancies in a BiOBr/g-C<sub>3</sub>N<sub>4</sub> Heterojunction for Sustainable Solar Ammonia Fertilizer Synthesis
Lei Zhang, Min Jiang, Hao Tian, Sixiao Liu, Xiaoyu Zhou, Hang Liu, Shaojie Gan, Shuya Che, Zhang Chen, Yuan Li, Tianyi Wang, Guoxiu Wang, Chengyin Wang
Abstract
Efficient and economical nitrogen fixation photocatalysts are one of the most attractive goals in ammonia-demanding agricultural production. Herein, a straightforward defect engineering and heterojunction strategy has been presented. Using in situ solvothermal techniques, a BiOBr/g-C 3 N 4 photocatalyst with oxygen and nitrogen double vacancies was achieved, and its NH 3 yields exceeded that of g-C 3 N 4 with a single N-vacancy and BiOBr with an O-vacancy by 23.5 and 2.9 times, respectively. Meanwhile, efficient spatial photocarrier separation was obtained through double vacancies and the interfacial interaction between the g-C 3 N 4 and BiOBr. Additionally, BiOBr/g-C 3 N 4 /polyacrylonitrile (PAN) microfibers and related waterwheel-like reactors were designed. Upon natural sunlight, these can conduct long-term nitrogen fixation using only air and water. Compared with the BiOBr/g-C 3 N 4 powder catalysts, BiOBr/g-C 3 N 4 /PAN microfiber catalysts exhibited higher stability and recoverability. The solar ammonia fertilizer produced by BiOBr/g-C 3 N 4 supplies crops with essential nutrients, which foster their growth. This has significant implications for reducing the expenses associated with conventional nitrogen fertilizers and contributing to environmental preservation.