Abstract: 1-Methyl-3-carboxymethyl imidazolium chlorine([C₂OOHmim]Cl) ionic liquid surface\|capped TiO₂ nanoparticles were prepared by using tetra-n-butyl titanate ethanol solution as a precursor. The structure of nanoparticles was characterized by FTIR, TEM, XRD and XPS. The results confirmed that [C₂OOHmim]·Cl ionic liquid combined with TiO₂ nanoparticles by chelation, the average diameter of TiO₂ nanoparticles was about 8 nm and anatase state was obtained. And only anatase existed even after calcinated at 750 ℃. As to the formation mechanism, we think that the inorganic-organic copolymerized surface-capped layer and repulsive force of positive charge played an important role in the formation and stabilization of TiO₂ nanoparticles.

Key words: Carboxyl-functionalized ionic liquid, TiO2 nanoparticles, Chelation, Surface-modification