The facile preparation of Ag decorated TiO2/ZnO nanotubes and their potent photocatalytic degradation efficiency

Abstract

Hollow TiO₂ and TiO₂/ZnO nanotubes were produced using a simple and novel approach combining electrospinning with an impregnation calcination method. Using a photoreduction method, silver nanoparticles (AgNps) were successfully decorated on the surface of nanotubes. During the synthesis process, the electrospinning procedure provided sacrificial templates for the fabrication of hollow nanotubes by producing PAN nanofibers, which can be immobilized on the TiO₂ surface through a soaking method. Later, the composite nanofibers of TiO₂/PAN were calcined into pure TiO₂ nanotubes after complete combustion of the sacrificial templates. The morphology of the samples was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The structure and components of the samples were characterized by X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX) and X-ray photoelectron spectroscopy (XPS). Upon blending ZnO into TiO₂, a new crystallite ZnTiO₃ was formed in addition to the ZnO and TiO₂ crystallites, and the ultra-violet light absorption efficiency was detected using UV-vis diffuse reflectance spectroscopy (DRS). The photocatalytic properties were evaluated using the degradation of methyl orange (MO) dye. As observed from the results, the Ag/TiO₂/ZnO nanotubes could degrade MO efficiently under UV irradiation, which showed excellent photocatalytic activity compared to pure TiO₂. The synthetic mechanism of Ag/TiO₂/ZnO nanotubes and the mechanism for the enhanced photocatalytic activity have been proposed.