Photocatalytic activity of Al/Ni doped TiO2 films synthesized by sol-gel method: Dependence on thickness and crystal growth of photocatalysts

Al and Ni doped TiO2 thin films were prepared via sol-gel dip-coating method. The effect of the photocatalysis process on the properties of TiO2 based thin films was investigated. The TiO2 based films were annealed at 450 degrees C. XRD results show that un-doped TiO2 films were grown with anatase phase, whereas, the Ni and Ni/Al doped TiO2 films show anorthic structure of Ti4O7 single phase. The presence of Al preferred the rutile phase. No phases related to NiO or Al2O3 were detected. Ni/TiO2 photocatalyst shows high photocatalytic activity (~93%) of Methylene blue (MB) breakdown thanks to the high content of O and Ti, wide band gap (3.35 eV), low crystalline size (6.87 nm), high film thickness (288 nm), and high surface roughness (44.5 nm). After photocatalysis, all the films show a decrease in O content and thickness, whereas the indirect band gap values were increased which suggests the reuse with low photocatalytic activity.

Automated summary

In this study, Al and Ni doped TiO2 thin films were prepared by sol-gel dip-coating method, and the effect of photocatalysis process on the properties of TiO2 based films was investigated. The experimental results showed that the Ni and Ni/Al doped TiO2 films exhibited high photocatalytic activity, as well as small grain size, large film thickness, and high surface roughness.