Photocatalytic Activity of Zn-doped TiO_2 Nanocrystals Synthesized by Diffusion Flame Combustion

Zinc-doped TiO2 nanocrystals were synthesized by diffusion flame method with titanium tetrachloride and zinc aceetylacetonate as raw materials,and their structures were characterized by XRD,ICP-AES and XPS.The catalytic activity of Zn-doped TiO2 nanocrystals on photodegradation of Rhodamine B was investigated under UV light irradiation and the mechanism was elaborated to demonstrate the improved photocatalytic activity of Zn-doped TiO2 nanocrystals.It is found that dopant Zn2+ ions are mostly located on the surface of TiO2 nanoparticle,and small ZnO nuclei dispersing randomly on the anatase TiO2 surface form,which has less effect on the crystalline phase and particle size.The best photocatalytic activity of 0.21%(mol) Zn-doped TiO2 nanoparticles is attributed to the enhancement of electron and hole segregation because of the difference in the energy band positions of TiO2 and ZnO.