Cu-doped Bi/Bi 2 WO 6 catalysts for efficient N 2 fixation by photocatalysis

In this paper, Cu-doped Bi 2 WO 6 was synthesized via a solvothermal method and applied it in photocatalytic N 2 immobilization. Characterization results showed the presence of a small amount of metallic Bi in the photocatalyst, indicating that the synthesized photocatalyst is actually Bi/Cu-Bi 2 WO 6 composite. The doped Cu had a valence state of +2 and most likely substituted the position of Bi 3+ . The introduced Cu did not affect the metallic Bi content, but mainly influenced the energy band structure of Bi 2 WO 6 . The band gap was slightly narrowed, the conduction band was elevated, and the work function was reduced. The reduced work function improved the transfer and separation of charge carriers, which mainly caused the increased photoactivity. The optimized NH 3 generation rates of Bi/Cu-Bi 2 WO 6 reached 624 and 243 (µmol·L −1 ·g −1 ·h −1 under simulated solar and visible light, and these values were approximately 2.8 and 5.9 times higher those of Bi/Bi 2 WO 6 , respectively. This research provides a method for improving the photocatalytic N 2 fixation and may provide more information on the design and preparation of heteroatom-doped semiconductor photocatalysts for N 2 -to-NH 3 conversion.