Fe Enhanced Visible-Light-Driven Nitrogen Fixation on BiOBr Nanosheets

Photocatalytic conversion of nitrogen (N2) to ammonia (NH3) requires strong binding of N2 onto the catalyst surface and the generation of photoexcited electrons to activate the N≡N bond. In this study, Fe is doped into BiOBr nanosheets, where the photoexcited electrons have enough energy to break the N≡N bond. The presence of Fe induces the formation of oxygen vacancies (OVs) in its vicinity, making it a photoexcited electron-rich region. The reduced Fe species effectively donates its available 3d orbital electron into the π N–N antibonding orbital to activate the adsorbed N2. With Fe as the active site, the N2 fixation rate of Fe-doped BiOBr is enhanced by eight times. This work provides a sustainable alternative for N2 photofixation and strategies for the catalyst design.