Comparison of Photocatalytic Activity of Bi 2 WO 6 /TiO 2 Nanotubes Heterostructures Composite under Multimode

Abstract

Bi 2 WO 6 /TiO 2 nanotubes (Bi 2 WO 6 /TiO 2 -NTs) heterostructures composite were synthesized by multicom-ponent assembly approach combined with hydrothermal treatment employed TiO 2 nanotubes as template. Multiple techniques such as X-ray powder diffraction (XRD), X-ray photo-electron spectroscopy (XPS), N 2 adsorption-desorption, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and UV-Vis diffused absorption spectra (UV-Vis DRS) were applied to investigate the composition, structures, morphologies, optical and electronic properties of as-prepared samples. The heterostructures were formed with Bi 2 WO 6 nanoflakes or nanoparticles attached on the surface of TiO 2 nanotubes. The photocatalytic activity of Bi 2 WO 6 /TiO 2 -NTs heterostructures was evaluated sufficiently by photodegradation of rhodamine B (RhB) under multimode including UV, visible and microwave-assisted photocatalysis. Compared to TiO 2 nanotubes and Bi 2 WO 6 , Bi 2 WO 6 /TiO 2 -NTs-35 shows the highest photocatalytic activity under multimode. In contrast with UV, visible mode, the Bi 2 WO 6 /TiO 2 -NTs-35 shows the highest activity toward RhB degradation under microwave-assisted photocatalytic mode. This enhanced photocatalytic activity is due to the more efficient separation of the e - -h + pairs, originating from the introduction of Bi 2 WO 6 modified TiO 2 -NTs, the nanotubular geometries, and degradation mode. The main active species of the degradation process are proven to be h + , ·OH, and ·O 2 - radicals. Moreover, more ·OH and ·O 2 - radicals were generated under microwave-assisted photocatalytic mode.