Photocatalytic Activity of TiO2-Doped Fe, Ag, and Ni with N under Visible Light Irradiation

Abstract

Doping with noble metal ions or doping with nitrogen has been attempted to prepare TiO2 that reacts even in visible light. In this study, TiO2 was doped with nitrogen and various metal ions instead of noble metals. The TiO2 photocatalysts doped with metal ions (Fe, Ag, Ni) and nitrogen were prepared by a sol-gel method. Their physicochemical properties were characterized and their photocatalytic activities were investigated under visible light irradiation. In TiO2 doped with metal ions and nitrogen, the light absorption region was extended to visible light. The photoluminescence intensity was much greater in N/Ni/TiO2 than in N/Ag/TiO2 and N/Fe/TiO2. The photolysis activities of N/Ni/TiO2 were the highest in formaldehyde decomposition and methylene blue decomposition. The sterilization efficiency of N/Ni/TiO2 was the highest in the evaluation test for the inhibition of the proliferation of Pseudomonas aeruginosa. The bandgap of N/Ni/TiO2 was 2.4 eV, which was significantly lower than that of anatase TiO2 (3.2 eV). The N/Ni/TiO2 had a much higher optical intensity than other metal ion-doped TiO2, so it was highly active under visible light irradiation.