Enhanced near-infrared photocatalytic activity of Bi3O4Br nanosheets via dual roles of rare earth ions doping: Photon conversion and energy band regulation

The efficient utilization of near-infrared (NIR) light is an important challenge to extend the spectral response range of photocatalysts. Here, the NIR photocatalytic performance of Bi 3 O 4 Br nanosheets was significantly enhanced by a rare earth ion doping strategy that synergistically utilizes the dual mechanism of photon conversion and energy band modulation. Under 980 nm excitation, the Bi 3 O 4 Br:Er 3 + nanosheets exhibit near-single-band green upconversion (UC) emission and are reabsorbed by Bi 3 O 4 Br. Combined with DFT density of states calculations, it is shown that the band gap of the material has been lowered and the carrier transport paths have been optimized by the energy-band structural tuning. In the NIR photocatalytic degradation experiment of bisphenol A, Bi 3 O 4 Br was not degraded, and Bi 3 O 4 Br:Er 3+ showed better performance, which was 2.27 times higher than that of Bi 3 O 4 Br:Yb 3+ , Er 3+ . ESR testing and capture experiments indicate that under NIR light irradiation, •OH and e − are the primary active species in the photocatalytic reaction process. This work provides new design ideas for the development of efficient NIR photocatalytic materials.