The effect of background irradiation on photocatalytic efficiencies of TiO2 thin films

TiO2 thin films were prepared on quartz pipe substrates. Effects of the thickness of the films, the wavelength of the UV light and La doping on efficiencies of background irradiated photocatalysis were investigated, and simultaneously was compared with those of foreground irradiated photocatalysis. The results showed that there was an optimal thickness of the film corresponding with each wavelength of the light source limited in the range from 300 nm to 388 nm in the case of background irradiated photocatalysis, which was quite different from that of foreground irradiated one. But in both cases, the film’s photocatalytic activities were enhanced by La non-uniformly doping. The results are useful for the design of high-efficiency photocatalytic reactors.