WO₃-Fe₂O₃/TiO₂ composite photocatalyst is an inorganic material which can be used in the degradation of pollutants in the environment, the new type of photocatalyst. Traditional photocatalyst is mainly based on titanium dioxide (TiO₂), which has the advantages of chemical stability, high catalytic activity, strong oxidizing power, non-toxic, low cost ect.; however, because the spectral response range of titanium dioxide is really narrow, and thus it can only utilize the ultraviolet light (wavelength less than 387nm), which has become the bottleneck and limited the application range of titanium dioxide. Therefore, the development of photocatalyst which has high activity and can utilize the visible light is of very large economic and practical value. 

 

Research has found that, doping metal ion is an effective way to make TiO₂ showing photocatalytic activity under visible light. Generally believed that the metal ions into the TiO₂ lattice can be introduced impurity levels in the forbidden band, the band gap is reduced, so that the valence band electrons after receiving a large optical excitation wavelength, the first transition to impurity energy level, by once again absorb the energy, the transition from the impurity level to the conduction band, thereby reducing the energy required by stimulated to achieve so that the spectral response range of TiO₂ photocatalytic move to the visible region. 

 

An invention has pointed out a method to prepare WO₃-Fe₂O₃/TiO₂ composite photocatalyst, which bases on the tungsten source of ammonium metatungstate (AMT), with the steps as following:

1. Add water into the ammonium metatungstate solution according to the weight ratio of WO₃: water (1：6〜7);

2. And then add ferric nitrate [Fe(NO₃)₃•9H₂O] according to the weight ration of WO₃: ferric nitrate (5〜7:1 ) to dissolve and get the impregnation liquid;

3. Add TiO₂ powder, which is anatase type with BET specific surface area of 80〜150m²/g, according to the weight ration of WO₃: TiO₂ (1：6〜7), then dry the mixture at 100°C for 4~6 hours;

4. Calcine the mixture at 580°C〜780°C for 5 hours to finally get WO₃-Fe₂O₃/TiO₂ composite photocatalyst.

 

Compared with the composite materials which dose not dope with metal ions, WO₃-Fe₂O₃/TiO₂ composite photocatalyst is showing a better photocatalytic ability; at the same time, the doping of WO₃ and Fe₂O₃ with specific lattice structure is actually modifying the TiO₂ particle, thus to extended spectral response range of TiO₂, and make it can be widely applied in the fields of environmental purification.