Synthesis of Au–CuS–TiO2 nanobelts photocatalyst for efficient photocatalytic degradation of antibiotic oxytetracycline

• A new type ternary Au–CuS–TiO2 NBs has been fabricated.
• The Au–CuS–TiO2 NBs shows superior photocatalytic activity.
• The oxytetracycline in aqueous solution can be removed by Au–CuS–TiO2 NBs.

Immobilized TiO2 nanobelts modified by Au and CuS nanoparticles (Au–CuS–TiO2 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 TiO2 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–TiO2 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–TiO2 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–TiO2 NBs, while only 85%, 76%, and 66% for Au–TiO2 NBs, CuS–TiO2 NBs, and TiO2 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–TiO2 NBs composite is an excellent photocatalyst with potential application in environmental remediation.