Modulation of bismuth vacancies on BiOCl surface by tungsten doping for photocatalytic nitrogen reduction

Photocatalytic nitrogen (N2) reduction reaction for solar energy conversion encounters considerable challenges due to the inadequate performance of semiconductor photocatalysts. The role of metal cation vacancies in photocatalytic nitrogen fixation is rarely explored. Here, we report a facile strategy to construct BiOCl nanosheets with tunable Bi-vacancy via tungsten doping. W-doped energy levels and Bi vacancies (VBi) can effectively tune the energy band structure of BiOCl, thereby broadening the range of light absorption and enhancing carrier transport. Density functional theory (DFT) calculation results reveal that the doped W6+ can act as the main activation sites of nitrogen for N equivalent to N elongation, and the Bi vacancies are the main adsorption sites with the strongest nitrogen adsorption energy. This results in the formation of dual active sites for nitrogen adsorption and activation. W-BiOCl-2 showed excellent nitrogen fixation efficiency of 1016.6 mu mol h- 1 g- 1, which was 2.6 times higher than that of pristine BiOCl without any sacrificial agents. This study provides a promising strategy for the design of high-performance photocatalytic N2 fixation catalysts with multiple active sites.