Visible-light-driven Ag/AgCl@In2O3: a ternary photocatalyst for the degradation of tetracycline antibiotics

摘要

The abuse of tetracycline antibiotics (TCs) has created great threats to both human health and the ecosystem. Therefore, developing efficient technologies to remediate these contaminants is of significant and practical interest. In this work, a ternary plasmonic Ag/AgCl@In2O3 nanocomposite was synthesized by growing AgCl on the surface of one-dimensional In2O3 nanorods, followed by the in situ photoreduction of Ag from AgCl on AgCl@In2O3. The as-synthesized Ag/AgCl@In2O3 nanocomposite exhibits excellent performance for the photocatalytic degradation of tetracycline (TTC) with a degradation rate constant of 0.166 min(-1), which is much better than that of pristine In2O3, Ag@In2O3, AgCl@In2O3, Ag/AgCl, and In2O3 + Ag/AgCl (the mechanical mixture of In2O3 and Ag/AgCl) samples. Five photocatalytic cycling tests demonstrate that Ag/AgCl@In2O3 possesses outstanding stability. In addition, Ag/AgCl@In2O3 also exhibits excellent photo-activity for the degradation of other types of tetracycline antibiotics, e.g. chlortetracycline (CTC) and oxytetracycline (OTC). Further trapping experiments prove that h(+) and O-2(-) are responsible for the photocatalytic reactions. The enhancement in the photoactivity of the Ag/AgCl@In2O3 system is largely due to the surface plasmon resonance effect (SPR) provided by the Ag nanoparticles, which inject electrons into AgCl and/or In2O3, and the efficient separation of photoinduced carriers is possible by transferring electrons to the conduction band of In2O3. This work provides a new type of photocatalyst towards the effective treatment of tetracycline antibiotics in aqueous systems.