The effects of Br dopant on the photo-catalytic properties of Bi2WO6

We present an experimental study on photocatalysis of pure and Br-doped Bi2WO6 powders, including photo-degradation of Rhodamine B, UV-vis absorption spectra and photo-luminescence spectrum. The obtained results indicate that Br-doped Bi2WO6 powders exhibit preferable photocatalytic activity than pure Bi2WO6. Then, the structural stability and the electronic properties of Br-doped Bi2WO6 are studied by employing the first-principles method, and a promising improvement of photo-catalytic activity is found in the visible-light region after doping, which is consistent with the experimental results. The Brie-doped structure is found to be more preferred, nevertheless all the three types of doping can narrow the band gap of Bi2WO6 pronouncedly, and thus the availability of solar energy increases consequently with the doping. On the other hand, the doping of Br results to smaller electron effective mass and induces impurity levels in gap, which is in favor of the carrier's transfer and the decrease of electron-hole recombination respectively. (c) 2016 Elsevier B.V. All rights reserved.