Experimental and theoretical studies of Fe-doped TiO sub(2) films prepared by peroxo sol-gel method

• Published in: Applied catalysis. A, General Vol. 401; no. 1-2; pp. 98 - 105
• Main Authors: Wellia, Diana V, Xu, Qing Chi, Sk, Mahasin Alam, Lim, Kok Hwa, Lim, Tuti Mariana, Tan, Timothy Thatt Yang
• Format: Journal Article
• Language: English
• Published: 15.07.2011
• Subjects: Absorbance; Charge; Doping; Glass; Heating; Iron; Sol-gel processes; Thin films; Titanium dioxide
• ISSN: 0926-860X
• DOI: 10.1016/j.apcata.2011.05.003

Transparent, uniform, crack-free and visible light activated Fe-doped TiO sub(2) thin films have been prepared by an organic-free approach using titanium tetrachloride (TiCl sub(4)), Fe super(3+) and ammonium hydroxide solutions to form yellow aqueous peroxo titanic acid (PTA) solution. Pure glass was made superhydrophilic after heating at 550 degree C for 1 h and was used as the coating substrate. The PTA solution dispersed uniformly on the superhydrophilic glass by forming a thin film, resulting in a crack-free Fe-doped TiO sub(2) film as observed under FESEM. XRD results confirmed the presence of only anatase phase for all samples after calcination at 550 degree C. The Fe-doped TiO sub(2) films exhibited slight red-shift in absorbance and enhanced absorbance in the visible-light region compared with undoped TiO sub(2), attributed to bandgap narrowing by successful Fe super(3+) doping into TiO sub(2), which is supported by dos calculations. Photodegradation of stearic acid (SA) revealed that Fe super(3+) doping increased visible light photocatalytic activity four-fold compared to undoped TiO sub(2) at optimal Fe-doped TiO sub(2) (1 wt% Fe super(3+)) film. At higher Fe ions concentrations, the existence of increased charge recombination sites and segregated iron oxide phase suppressed the photoactivity.