Nanocrystalline Fe/TiO₂ Visible Photocatalyst with a Mesoporous Structure Prepared via a Nonhydrolytic Sol−Gel Route

Abstract

Fe-doped nanocrystalline TiO 2 (Fe/TiO 2 ) with a mesoporous structure was prepared via a facile nonhydrolytic sol−gel (NSG) route. During photodegradation of methylene blue under visible light irradiation, as-prepared Fe/TiO 2 exhibited a higher activity than either the undoped TiO 2 or the Fe/TiO 2 obtained via the traditional hydrolytic sol−gel route. The correlation of the photocatalytic performance to the structural characteristics is discussed based on detailed characterizations. The promoting effect of the Fe-doping on the photocatalytic activity could be attributed to the formation of intermediate energy levels that allow Fe/TiO 2 to be activated easily in the visible area. The optimum Fe-content in Fe/TiO 2 is determined as 0.1% (Fe/Ti molar ratio). The nonhydrolytic sol−gel method is superior to the traditional hydrolytic sol−gel method owing to the controllable reaction rate and lack of surface tension, which ensures the formation of mesopores and well-crystallized anatase in the Fe/TiO 2 sample, leading to a higher activity since the reactant molecules are easily adsorbed and the recombination between the photoelectrons and the holes is effectively inhibited. Meanwhile, the nonhydrolytic sol−gel process could strengthen the incorporation of Fe-dopants in the TiO 2 network, which may further enhance the promoting effect of Fe-doping on the photocatalytic activity.