One-step synthesis of BiOCl/Bi4NbO8Cl heterostructures with high-purity and enhanced photocatalytic activities via in-situ room-temperature acid-etching

In this study, BiOCl/Bi4NbO8Cl heterojunctions with improved photocatalytic performance were designed and synthesized by in-situ room-temperature acid-etching. Bi4NbO8Cl prepared by the solid-phase method was often accompanied by certain impurities, such as Bi24O31Cl10 and Bi3NbO7. With the assistance of glacial acetic acid, the impurities could be eliminated. At the same time, BiOCl nanosheets were formed in situ at room temperature, and BiOCl/Bi4NbO8Cl (BBN) heterostructures were obtained. For comparison, pure Bi4NbO8Cl was prepared using the molten salt method (S-BNC). Compared to S-BNC, BBN exhibited better performance in degrading rhodamine B (RhB) and ciprofloxacin (CIP). The mechanism of the improved photocatalytic activities was studied by analyzing photoluminescence spectra, UV–vis diffuse reflection absorption spectra, and cyclic voltammetry curves.