Comparison of Photocatalytic Activity of Bi2WO6/TiO2 Nanotubes Heterostructures Composite under Multimode

Bi2WO6/TiO2 nanotubes (Bi2WO6/TiO2-NTs) heterostructures composite were synthesized by multicomponent assembly approach combined with hydrothermal treatment employed TiO2 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 Bi2WO6 nanoflakes or nanoparticles attached on the surface of TiO2 nanotubes. The photocatalytic activity of Bi2WO6/TiO2-NTs heterostructures was evaluated sufficiently by photodegradation of rhodamine B (RhB) under multimode including UV, visible and microwave-assisted photocatalysis. Compared to TiO2 nanotubes and Bi2WO6, Bi2WO6/TiO2-NTs-35 shows the highest photocatalytic activity under multimode. In contrast with UV, visible mode, the Bi2WO6/TiO2-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 Bi2WO6 modified TiO2-NTs, the nanotubular geometries, and degradation mode. The main active species of the degradation process are proven to be h(+), center dot OH, and center dot O-2(-) radicals. Moreover, more center dot OH and center dot O-2(-) radicals were generated under microwave-assisted photocatalytic mode.