Pure and (zinc or iron) doped titania powders prepared by sol-gel and used as photocatalyst

摘要

Pure and doped (zinc and iron) nanocrystalline titania powders were prepared by the sol-gel route. Doping tends to change the existing crystalline phases and their degree of crystallinity, but particle size distribution and morphology of the particles are also affected. In the pure titania system, the main crystalline phase is anatase but rutile is also present. The doped (Zn and Fe) titania crystallizes only as anatase. The undoped titania shows a bimodal distribution of particles size: fine (20-40 nm) and coarse (300-500 nm) grains. The doped TiO_2 powder also exhibits a much more uniform particle size distribution, with all grains under 40 nm.