Photocatalytic nitrogen fixation has been considered to be a safe, green, eco-friendly, and sustainable technology. However, photoinduced activation of inert dinitrogen is an important factor hindering the development of this technology. Herein, in-situ Fe3+ doped flower-like BiOCl with highly active sites exposure was prepared by a solvent thermal method, which has excellent performance of N-2 photofixation. Compared with virgin BiOCl with no nitrogen fixation activity, Fe-BiOCl reached 30 mu mol.L-1.h(-1) ammonia evolution rate under simulated sunlight without any sacrificial reagent. Characterization results demonstrated that the enhancement of N-2 photofixation capacity was mainly attributed to the in-situ doped Fe3+ in BiOCl, the doped Fe3+ not only acts as a reaction center for N-2 activation also as an "electron transfer bridge" trapping and migrating electrons from BiOCl to N-2 molecules. Furthermore, the transformation of crystal facets from virgin BiOCl (001) to Fe-BiOCl (110) and (102) is more conducive for the exposure and accessibility of iron reactive sites. This work developed a potential strategy by in-situ introducing Fe3+ active sites in BiOCl semiconductor substrate, which establishes a good basis for the application of semiconductor catalysts in nitrogen fixation. (C) 2020 Elsevier Inc. All rights reserved.