Improved visible light photocatalytic activity of TiO<inf>2</inf> nano powder by Ce<sup>3+</sup> doping

Abstract

It is well known that titanium dioxide photocatalyst can only be effectively activated by ultraviolet light due to its high band gap energy and therefore it is very essential to reduce the band gap energy by shifting the absorption wavelength to the visible region. Research has shown that doping TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> with metallic ions revealed promising results. In this study TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> was doped with cerium and the powder was prepared by sol-gel method and was characterized by X-ray diffraction (XRD), UV/Vis diffused reflectance spectroscopy (DRS) and scanning electron microscope (SEM). The photocatalytic activity under visible light was evaluated by photocatalytic degradation of methylene blue in water using UV/Vis spectrophotometer. Findings indicated that higher Ce <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> content resulted in shifting of absorption edge to longer wavelength which consequently lowered the band gap energy. At 1.0 wt% Ce-doped TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , offered lowest band gap at 2.64 eV and thereby the best photocatalytic activity was achieved. At this cerium content doping, the recombination of photo-induced electron and holes could be effectively inhibited.