Photocatalytic degradation properties of V-doped TiO_2 to automobile exhaust

摘要

To improve the photocatalytic degradation properties of titanium dioxide (TiO_2) used as raw materials for purifying automobile exhaust (AE), the vanadium (Ⅴ)-doped TiO_2 samples were prepared. The photocatalytic degradation efficiencies of V-doped TiO_2 to each component in AE were evaluated under ultraviolet (UV) and visible light irradiation, respectively. Results indicated that the photocatalytic activity of V-doped TiO_2 to AE was higher than that of pure TiO_2, and the optimal V dopant content of TiO_2 was 1.0% under UV light irradiation. The degradation efficiencies of V-doped TiO_2 to NOx and HC were higher than those to CO_2 and CO in AE because of the reversible reaction between CO_2 and CO. In addition, it was found that the photocatalytic degradation efficiencies of V-doped TiO_2 to each component in AE were also increased under visible light irradiation. The V-doped TiO_2 also showed higher degradation efficiencies to NOx and HC than those to CO_2 and CO under visible light irradiation. The V doped TiO_2 presented higher photocatalytic activity to CO_2 than that to CO, but the reversible reaction between CO and CO_2 was not found under visible light irradiation. The photocatalytic reactions of pure and V-doped TiO_2 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 TiO_2 to AE for air purification, developing a sustainable environmental purification technology based on TiO_2 materials.