Double metals sites synergistically enhanced photocatalytic N fixation performance over BiOBr@Bi/TiCT Ohm junctions.

At present, it is a research hotspot to realize green synthetic ammonia by using solar energy. Exploring cheap and efficient co-catalysts for enhancing the performance of photocatalysts is a challenge in the field of energy conversion. In order to boost the charge separation/transfer of the photocatalyst and widen the visible light absorption, BiOBr@Bi/TiCT with double Ohm junction is successfully fabricated by in situ growth of metal Bi and loading TiCT MXene on the surface of BiOBr. The dual active sites of Bi and TiCT MXene not only broaden the light adsorption of BiOBr but also serve as excellent 'electronic receptor' for synergically enhancing the separation/transfer efficiency of photogenerated electrons/holes. Meanwhile, temperature programmed desorption (TPD) result revealed that MXene and Bi can promote N adsorption/activation and NH desorption over BiOBr@Bi/TiCT. As a result, under mild conditions and without the presence of hole scavenger, the ammonia synthesis efficiency of BiOBr@Bi/TiCT-20 % reached 53.86 μmol g for three hours which is 3.2 and 53.8 times of BiOBr and TiCT, respectively. This study offers a novel scheme for the construction of photocatalytic systems and demonstrates TiCT MXene and metal Bi as a promising and cheap co-catalyst.