Abstract
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•Novel In2S3/InVO4 heterojunction prepared by a facile in-situ anion exchange method.•In2S3/InVO4 exhibited much enhanced photocatalytic activity for TC degradation.•Anion exchange preserved the morphology and structure while enhancing the activity.•The photo-degradation is dominated by the hole and O2− while without OH radicals.•Enhanced charge separation and light absorption are obtained for In2S3/InVO4.
Semiconductor heterostructures have attracted extensive interest in photocatalytic degradation of antibiotic pollutants. In this study, a novel In2S3/InVO4 heterojunction was prepared via a simple in-situ anion exchange method by reacting pre-synthesized InVO4 microspheres with Na2S in an aqueous solution. The structures, morphologies and optical properties of the as-prepared samples were well characterized by XRD, SEM, EDS, TEM, XPS, N2 adsorption–desorption, UV–Vis absorption spectra, PL, photocurrent and electrochemical impedance spectroscopy. Benefiting from the enlarged visible light response and the formation of heterostructure, the as-prepared In2S3/InVO4 microspheres exhibit significantly promoted photocatalytic performance for the degradation of tetracycline (TC) under visible-light illumination. The optimum photocatalytic efficiency of In2S3/InVO4 composite was almost 2.26 and 11.71 times higher than that of In2S3 and InVO4, respectively. It also exhibited remarkable stability and repeatability. Radical trapping experiment and electron spin resonance results indicate that h+ and O2− are the main active species in the reaction system, and the role of OH can be ignored. The detailed photocatalytic mechanism is also proposed.