Highly active Fe sub(2)O sub(3)-doped TiO sub(2) photocatalyst for degradation of trichloroethylene in air under UV and visible light irradiation: Experimental and computational studies

0.0-5.0wt% Fe sub(2)O sub(3)-doped TiO sub(2) photocatalysts were synthesized by an ultrasonic-assisted coprecipitation method and used for degradation of 500 ppm trichloroethylene. (TCE) in air. The photocatalysts were treated at 100-400 [degrees]C and characterized by high resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (XRD), BET surface area, and Raman, UV-vis, and photo-luminescence (PL) spectroscopies. For the samples treated at 100[degrees]C, XRD patterns show no significant peaks, while HRTEM micrographs indicate crystalline structures and diffraction patterns and Raman spectra reveal wide and weak peaks of anatase TiO sub(2). As 0.1 wt% Fe sub(2)O sub(3) is added to TiO sub(2), the surface area increases by a factor of 1.87 and reach to 448 m super(2)/g. UV-vis analyses indicate that, as the Fe sub(2)O sub(3) content of the samples increases, the band gap energies decrease from 3.22 eV for the pure TiO sub(2) to 2.60 eV for 5.0 wt% Fe sub(2)O sub(3)-doped TiO sub(2). Density functional theory simulations show that, when Fe super(3+) is doped into or FeO, Fe sub(2)O sub(3) or Fe sub(4)O sub(6) is adsorbed on anatase TiO sub(2), the bad gap reduces and the iron oxide-TiO sub(2) show photocatalytic activity in visible light region. The synthesized TiO sub(2) showed about two times higher photocatalytic activity for TCE removal than that of Degussa P25. Moreover, 0.1 wt% Fe sub(2)O sub(3)-doped TiO sub(2) sample dried at 100[degrees]C showed a maximum photocatalytic TCE conversion of about 97% with minor amounts of CO as a hazardous byproduct. As the treatment temperature of the samples increase, the photocatalytic activity declines. Significant photocatalytic degradation of TCE was also observed for the Fe sub(2)O sub(3)-doped TiO sub(2) samples, under visible light irradiation.