Nucleation−Growth of TiO2 Nanoparticles Doped with Iron Acetylacetonate

Abstract

We report on the preparation of Fe-doped TiO2 nanoparticles by a sol−gel route using a titanium tetraisopropoxide precursor. A turbulent micromixing of the injected fluids enables homogeneous reaction conditions in the reactor bulk and monodispersity of the produced nanoparticles. The dopant iron acetylacetonate Fe(acac)3 is injected into the solution at the nucleation stage. The doping agent takes surface sites of TiO2 nanoparticles resulting in the Fe(acac)2−TiO2 complex. The reaction progresses by elimination of the residual acetylacetate until the formation of the Fe−TiO2 complex, in which Fe can coordinate three TiO2 nanoparticles. The released acac groups take surface sites of the composite nanoparticles and slow down the induction kinetics. We show that the micromixing quality is critical even in the case of the apparently slow sol−gel induction kinetics.