Synergistic Effects of Fluorine and WO3 Nanoparticles on the Surface of TiO2 Hollow Spheres for Enhanced Photocatalytic Activity under Visible Light Irradiation.

Abstract

TiO2 is an attractive catalyst for the photocatalytic degradation of organic pollutants. However, owing to its large band gap, it can only be activated by ultraviolet (UV) light, which constitutes a small portion of solar energy. Therefore, there has been significant interest in extending its light absorption range from UV to visible light. In this study, fluorinated TiO2 hollow spheres (FTHSs) were prepared via a rapid and simple wet chemical process using ammonium hexafluorotitanate, and then FTHS/WO3 heterostructures with different weight ratios of the FTHS and WO3 nanoparticles were synthesized via a simple wet impregnation method. The formation of the hybrid structure was confirmed by various characterization techniques. The photocatalytic activity of the synthesized photocatalysts in the photodegradation of rhodamine B, a model pollutant, was evaluated under visible light irradiation. The FTHS/WO3 heterostructures exhibited significantly improved photocatalytic activity compared to the bare FTHS or WO3 nanoparticles. The photodegradation efficiency of the FTHS/WO3 heterostructure in the present study was up to 0.0581 min–1. Detailed mechanisms that lead to the enhanced photocatalytic activity of the heterostructures are discussed. In addition, comparative experiments reveal that the photodegradation efficiency of the FTHS/WO3 heterostructure under visible light irradiation is superior to that of the P25/WO3 heterostructure prepared from the commercially available TiO2 catalyst (P25) via the same impregnation method.