Photocatalytic degradation properties of V-doped TiO2 to automobile exhaust

Abstract

To improve the photocatalytic degradation properties of titanium dioxide (TiO₂) used as raw materials for purifying automobile exhaust (AE), the vanadium (V)-doped TiO₂ samples were prepared. The photocatalytic degradation efficiencies of V-doped TiO₂ to each component in AE were evaluated under ultraviolet (UV) and visible light irradiation, respectively. Results indicated that the photocatalytic activity of V-doped TiO₂ to AE was higher than that of pure TiO₂, and the optimal V dopant content of TiO₂ was 1.0% under UV light irradiation. The degradation efficiencies of V-doped TiO₂ to NOx and HC were higher than those to CO₂ and CO in AE because of the reversible reaction between CO₂ and CO. In addition, it was found that the photocatalytic degradation efficiencies of V-doped TiO₂ to each component in AE were also increased under visible light irradiation. The V-doped TiO₂ also showed higher degradation efficiencies to NOx and HC than those to CO₂ and CO under visible light irradiation. The V doped TiO₂ presented higher photocatalytic activity to CO₂ than that to CO, but the reversible reaction between CO and CO₂ was not found under visible light irradiation. The photocatalytic reactions of pure and V-doped TiO₂ samples to each component in AE followed the first order kinetic pathway under the two light irradiations. It is concluded that the V doping is a feasible method to improve the photocatalytic degradation properties of TiO₂ to AE for air purification, developing a sustainable environmental purification technology based on TiO₂ materials.

Keywords: Automobile exhaust; Photocatalytic degradation property; Titanium dioxide; Vanadium doping; Visible light.