Construction of novel Cu2O/PbBiO2Br composites with enhanced photocatalytic activity

In this work, novel Cu2O/PbBiO2Br heterojunction composites have been successfully prepared by hydrothermal method and oxidation-reduction process. The structure, morphology, optical and electronic properties of the as-prepared photocatalysts were investigated by various techniques. It is demonstrated that PbBiO2Br appears a smooth brick-like nanostructure and the average size is about 20-110nm. The PbBiO2Br nano-bricks are dispersed on the surface of Cu2O particles to form Cu2O/PbBiO2Br p-n heterostructures. Compared with pure PbBiO2Br and Cu2O, the Cu2O/PbBiO2Br heterojunction composites exhibit enhanced photocatalytic performances for the degradation of crystal violet (CV) solution under visible-light irradiation. In particular, the 5%Cu2O/PbBiO2Br composite shows the optimal photocatalytic performance, and the degradation efficiency of CV reaches 96% in 50min. The enhanced photocatalytic performance of the Cu2O/PbBiO2Br composites can be attributed to the significantly enhanced absorption in the visible range and efficient separation of photo-generated electron-hole pairs due to the formation of Cu2O/PbBiO2Br p-n heterostructures. Furthermore, the radical trapping experiments indicate that O2- radicals and holes are the main active species during the decomposition process. Based on the experimental results and analyses, a possible photocatalytic mechanism of the Cu2O/PbBiO2Br composites is proposed. This study reveals that the Cu2O/PbBiO2Br composite photocatalysts could be applied in the wastewater purification.