Enhanced ambient ammonia photosynthesis by Mo-doped Bi5O7Br nanosheets with light-switchable oxygen vacancies

The fabrication of efficient catalysts to reduce nitrogen (N2) to ammonia (NH3) is a significant challenge for artificial N2 fixation under mild conditions. In this work, we demonstrated that the simultaneous introduction of oxygen vacancies (OVs) and Mo dopants into Bi5O7Br nanosheets can significantly increase the activity for photocatalytic N2 fixation. The 1 mol% Mo-doped Bi5O7Br nanosheets exhibited an optimal NH3 generation rate of 122.9 μmol g−1 h−1 and durable stability, which is attributed to their optimized conduction band position, suitable absorption edge, large number of light-switchable OVs, and improved charge carrier separation. This work provides a promising approach to design photocatalysts with light-switchable OVs for N2 reduction to NH3 under mild conditions, highlighting the wide application scope of nanostructured BiOBr-based photocatalysts as effective N2 fixation systems.