Preparation of La³⁺, carbon nanotube doped nanometer TiO₂ with sol-gel method and photocatalytic activity of doped nanometer TiO₂

Three kinds of doped TiO₂ particles, include La³⁺ doped, multi-wall carbon nanotube (MWCNT) doped and their co-doped TiO₂, were prepared by sol-gel method. The catalytic activity of doped TiO₂ was evaluated via ultraviolet light degradation experiments of methyl orange. It is found that La³⁺ doped TiO₂ particles demonstrates a higher photocatalytic activity than that of pure TiO₂, and an optimum value is reached at doped concentration of 0.08% (mole fraction). CNT doped TiO₂can also improve the photocatalytic activity of TiO₂. Besides, TiO₂ particles co-doped with La3+and CNT show the highest photocatalytic activity. As for co-doped TiO₂, the decomposition ratio of methyl orange solution reaches 84% in 1 h, while it gets 53% for pure TiO₂. The microstructure of the particles is characterized with XRD and TEM techniques. These particles are endowed with anatase crystal phase of about 8-25 nm diameter.