One-step in-situ synthesis of Bi-decorated BiOBr microspheres with abundant oxygen vacancies for enhanced photocatalytic nitrogen fixation properties

The conversion of atmospheric nitrogen (N-2) to ammonia (NH3) under mild conditions is quite challenging due to high stability of the triple covalent bond. Here we report that Bi-decorated BiOBr microspheres with plentiful oxygen vacancies (OVs) were successfully fabricated by one-step solvothermal strategy and used as effective photocatalysts for nitrogen fixation. The metallic Bi was reduced in-situ by glycerol and deposited on the surface of BiOBr microspheres. The synchronously generated OVs can serve as the activation center for nitrogen. Compared to pure BiOBr, Bi@BiOBr hetero-structured microspheres have higher specific surface area, superior visible-light utilization, more effective separation of photoexcited charge carriers, thus exhibiting more pronounced visible light photocatalytic N-2 fixation performance. Specifically, the N-2 reduction rate of the Bi@BiOBr-2 is 1350 mu mol g(-1-) h(-1), which is 11.8 times higher than pure BiOBr (114 mu mol h(-1)). This study provides a simple and low energy consumption method for effective and stable photocatalytic N-2 fixation.

Automated summary

Bi-decorated BiOBr microspheres with oxygen vacancies were fabricated using a solvothermal strategy, serving as effective photocatalysts for nitrogen fixation. The hetero-structured microspheres exhibited superior visible-light utilization and effective separation of photoexcited charge carriers, resulting in significantly enhanced N-2 fixation performance compared to pure BiOBr. This study offers a simple and energy-efficient method for stable photocatalytic N-2 fixation.