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 20–110 nm. 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 50 min. 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 \(\cdot {\text{O}}_{2}^{ - }\) 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.