One-pot synthesis of belt-like Bi2S3/BiOCl hierarchical composites with enhanced visible light photocatalytic activity

Abstract

One-dimensional (1D) belt-like Bi2S3/BiOCl composites were synthesized by a facile one-pot solvothermal method, using bismuth subsalicylate as the Bi source and, in particular, as the morphological template. The synthesized composites were characterized by many techniques, such as XRD, SEM, XPS, TEM and UV–vis diffuse reflectance and photoluminescence spectra. Photocatalytic activity of the composites was evaluated via catalytic degradation of salicylic acid (SA) and Rhodamine B (RhB) under visible light irradiation. The belt-like composites show a heterojunction structure in which the Bi2S3 nanoparticles are uniformly dispersed in the BiOCl matrix with dominant exposed (010) facets. They exhibit enhanced photodegradation efficiency in comparison with pure belt-like Bi2S3 and BiOCl. With increasing Bi2S3 content, the photodegradation efficiency of the composites increases then decreases. The Bi2S3/BiOCl composite with a Bi2S3 content of ∼2% exhibits the highest photocatalytic activity. The apparent first-order photodegradation rate constants of the composite for SA (∼0.048h−1) and RhB (∼0.299min−1) are significantly higher than those of the pure BiOCl and Bi2S3 for SA (∼0 and ∼0.0007h−1) and RhB (∼0.102 and ∼0.002min−1), respectively. The enhancement in photocatalytic activity is attributed to the efficient separation of photoinduced electrons and holes along with the increased specific surface area and visible-light absorption. The holes and superoxide radicals are the major active species. In addition, the belt-like Bi2S3/BiOCl photocatalysts exhibit excellent stability and reusability. This work provides a facile strategy for synthesis of 1D hierarchical Bi-based composite photocatalysts, and demonstrates the potential of belt-like Bi2S3/BiOCl composites for application in environmental remediation.