1-Methyl-3-carboxymethyl imidazolium chlorine（\C2OOHmim\Cl） ionic liquid surface-capped TiO 2 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 \KG-1/5C2OOHmim\·Cl ionic liquid combined with TiO 2 nanoparticles by chelation, the average diameter of TiO 2 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 TiO 2 nanoparticles.
