Efficient visible light photocatalytic oxidation of NO on F-, N-codoped spherical TiO₂ synthesized via ultrasonic spray pyrolysis

Abstract

The fluorine- and nitrogen-codoped TiO₂ was synthesized by ultrasonic spray pyrolysis method with titanium tetrafluoride and urea as precursor. The codoped TiO₂ was characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS), and X-ray photoelectron spectroscopy (XPS). Nitric oxide (NO) photocatalytic oxidation in gas-phase medium was employed as a probe reaction to evaluate the photocatalytic reactivity of the catalysts. The results indicated that spherical codoped TiO₂ photocatalysts with unique puckered surface were obtained by this method. The codoped catalysts have solely anatase crystalline structure. The optical characterization of the codoped catalysts showed that the codoped samples could be excited by visible light photons in the 400–550nm and could efficiently oxidize NO under visible light irradiation. The mechanism of special morphology formation of prepared codoped TiO₂structure is also discussed.