Mechanochemical synthesis of SrTiO_3-xF_x with high visible light photocatalytic activities for nitrogen monoxide destruction

Fluorine doped SrTiO₃ powders were prepared by a mechanochemical reaction method. The powders consisted of spherical particles of 20 nm and 0.1-0.2 μm in diameter. The photocatalytic activities of SrTiO₃ for the oxidative decomposition of NO under visible light (λ > 400 nm) and near ultraviolet light (λ > 290 nm) irradiation were greatly improved by the fluorine doping. Fluorine doping in the SrTiO₃ lattice enhanced its photocatalytic activity under irradiation with visible light (λ > 400 nm) ca. three times. It was also found that the photocatalytic activities of SrTiO_3-xF _x under both visible light and near ultraviolet light irradiation were higher than those of commercial titania powder (Degussa P-25).