Ti/Si, Fe/Ti, Fe/Ti/Si complex particles of different Ti and Fe contents were prepared by the sol-gel method and used as photocatalysts. The photocatalytic reactivity of these catalysts were investigated as a function of the Ti and Fe contents during the liquid-phase oxidation of tetracycline, which showed a dramatic enhancement at low Fe content. The UV-vis, FT-IR, XRD, XPS and Raman spectra investigation indicated that the titanium oxide particles anchored onto Si-O-Si tetrahedral network were highly dispersed with the size being about 10nm to 12nm in the Ti/Si, Fe/Ti/Si complex particles. The Fe/Ti/Si complex particles were proved to be the optimum photocatalysts in the present reaction. The promoting effects were attributed to the cooperation function of the multi-components, the generation of active .OH radicals and the intermediate midgap in the titanium oxide semiconductor caused by Fe^3^+. The TiO~2 particles existed in the low crystalline anatase phase and formed Si- O-Ti, Ti-O-Fe tetrahedral coordination network due to the inclusion of Ti^4^+ and Fe^3^+ ions into the SiO~2 matrix. These catalysts had significant surface defects, large specific surface area and high photocatalytic reactivity related to fast electron and hole separation. It was found that titanium oxide semiconductor particles of low crystalline anatase-rutile mixed phases of about 16nm in size and existed in the Ti-O-Fe tetrahedral coordination network due to the inclusion of Fe^3^+ ions into the TiO~2 matrix in the Fe/Ti complex particles. The titaium oxide semiconductor doped with Fe^3^+ enhanced UV light absorption and activity in the degradation of organic pollutants due to the highly surface defects and the formation of intermediate gap state. But, these particle size increased and stabilization was lower as compared to Ti/Si complex particles. The highly dispersed and highly stable Fe/Ti/Si complex particles existed in the Fe~2O~3, Fe~3O~4, FeO species and Si-O-Si, Ti-O-Ti, Si-O-Ti, Ti-O-Fe tetrahedFe/Ti/Si复合微粒的表面结构与催化活性

Key words: COMPLEX, PHOTOCATALYST, IRON COMPOUNDS, TITANIUM COMPOUNDS, SILICON COMPOUNDS, LIGHT DEGRADATION, DOPE, TETRACYCLINUM, PARTICLES, SURFACE STRUCTURE