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

The fabrication of efficient catalysts to reduce nitrogen (N 2 ) to ammonia (NH 3 ) is a significant challenge for artificial N 2 fixation under mild conditions. In this work, we demonstrated that the simultaneous introduction of oxygen vacancies (OVs) and Mo dopants into Bi 5 O 7 Br nanosheets can significantly increase the activity for photocatalytic N 2 fixation. The 1 mol% Mo-doped Bi 5 O 7 Br nanosheets exhibited an optimal NH 3 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 N 2 reduction to NH 3 under mild conditions, highlighting the wide application scope of nanostructured BiOBr-based photocatalysts as effective N 2 fixation systems.