BiOClxBryIz (x plus y plus z=1) solid solutions with controllable band gap and highly enhanced visible light photocatalytic performances

A series of BiOClxBryIz solid solutions with controllable band gap and highly enhanced visible light photocatalytic performances were synthesized by a simple hydrolysis method. The samples were characterized by X-ray powder diffraction, UV-vis diffuse reflectance spectra, scanning electron microscope, high-resolution transmission electron microscopy and Brunauer-Emmett-Teller analysis. By adjusting the molar ratio of halogen ions, the band gap of BiOC(l)xBr(y)I(z) could be controllable to the suitable value for a photocatalytic reaction. Especially, BiOClxBryIz with a 1: 1: 2 molar ratio of Cl, Br to I showed the highest visible light photocatalytic activity for the degradation of methyl orange than individual BiOX systems. The degradation efficiency could reach over 90% within 60 min. The possible mechanism of photogenerated carrier transfer and higher photocatalytic activity was analyzed by active species trapping and energy band theory. (C) 2015 Elsevier B.V. All rights reserved.