Photocatalytic performance of TiO2/Bi2WO6 photocatalysts with trace Fe3+ dopant for gaseous toluene decomposition

As one of the typical volatile organic compounds, toluene is harmful to human health and challenging to decompose effectively with traditional photocatalysts, such as TiO 2 or ZnO. Here, a trace Fe 3+ doped TiO 2 /Bi 2 WO 6 composite photocatalyst with abundant oxygen vacancies was successfully synthesized via a hydrothermal method and subsequently impregnation treatment. The Fe 3+ doped TiO 2 /Bi 2 WO 6 were optimized by adjusting the molar ration of TiO 2 and Bi 2 WO 6 , and the optimal molar ratio was found to be TiO 2 :Bi 2 WO 6 = 1:2. The obtained Fe (0.1) -TB 2 with only 0.1 wt% Fe 3+ dopant exhibited superior photocatalytic activity with over 90% toluene removal efficiency after 180 min under visible light irradiation. A series of characterizations reveal that the improved photocatalytic activity of Fe 3+ doped TiO 2 /Bi 2 WO 6 can be attributed to synergistic effects between the extension of photogenerated carrier lifetime and the increase of visible light absorption range by narrowing the energy bandgap (shortened about 0.32 eV) and the formation of oxygen vacancies. Furthermore, hydroxyl radicals and holes as the key reactive oxygen species (ROS) in the photodegradation reaction were confirmed by electron spin resonance (ESR) experiments. Therefore, introducing Fe-ions into TiO 2 /Bi 2 WO 6 photocatalysts is an effective way to enhance the photocatalytic activities, and the modified catalysts can be considered as a promising material for decomposing toluene and other VOCs.