Controlled hydrothermal synthesis of PbBiO2Br/BiOBr heterojunction with enhanced visible-driven-light photocatalytic activities

This is the first report that PbBiO2Br/BiOBr is synthesized by a template-free hydrothermal method. The composition and morphologies of the samples could be controlled by adjusting some growth parameters, including reaction pH, Pb/Bi molar ratio, and temperature. All the samples are characterized by XRD, TEM, XPS, SEM-EDS, Fr-IR, BET, EPR, and UV-vis-DRS. The PbBiO2Br/BiOBr photocatalysts exhibit enhanced photocatalytic activities on the degradation of crystal violet (CV) under visible-light irradiation. In particular, the catalytic performance illustrates the best reaction rate constant 1.257 x 10(-1) h(-1) once PbBiO2Br/BiOBr is used as the photocatalyst; which is 3 and 2 times higher than the reaction rate constant of PbBiO2Br and BiOBr being the photocatalysts, respectively. This study reveals that PbBiO2Br/BiOBr can be used to suppress the recombination of photoinduced electron-hole pairs and contribute to the enhanced photocatalytic efficiency of semiconductors in the visible-light-driven catalysis. The possible photodegradation mechanism is studied by examining different active species through EPR and adding appropriate scavengers. The results demonstrate that the reactive O-2(-) plays the major and OH the minor roles in the CV degradation. (C) 2016 Elsevier B.V. All rights reserved.