Synthesis of Au–CuS–TiO 2 nanobelts photocatalyst for efficient photocatalytic degradation of antibiotic oxytetracycline

Abstract Immobilized TiO 2 nanobelts modified by Au and CuS nanoparticles (Au–CuS–TiO 2 NBs) were successfully synthesized and employed in environment purification. The analysis of SEM, TEM, XRD, XPS, and EDX indicated that Au and CuS are deposited onto TiO 2 NBs. The UV–vis absorption spectra measurement showed that the loading of Au and CuS nanoparticles enhances the absorption intensity in visible light region, resulting in more efficient utilization of solar spectrum. The results of photoelectrochemical (PECH) and photoluminescence (PL) detections demonstrated that the incorporated Au–CuS–TiO 2 NBs nanostructure markedly retard the recombination of photogenerated electron–hole pairs owing to the efficient interfacial charge transfer, and then increase the number of charge carriers participating in photocatalysis. Therefore, the ternary complex Au–CuS–TiO 2 NBs displayed superior photocatalytic (PC) activity. In particular, an approximate 96% of the antibiotic oxytetracycline (OTC) molecules in aqueous solution were decomposed after simulated solar irradiation of 1 h for Au–CuS–TiO 2 NBs, while only 85%, 76%, and 66% for Au–TiO 2 NBs, CuS–TiO 2 NBs, and TiO 2 NBs, respectively. The reaction intermediates of OTC were identified by high resolution LC–MS, and six degradation intermediates were observed during the photocatalytic process. The possibly photocatalytic degradation pathway of OTC was proposed. This study demonstrates that the ternary Au–CuS–TiO 2 NBs composite is an excellent photocatalyst with potential application in environmental remediation.