Synthesis of TiO₂ Nanowires

Prof. Dr. Tilman Butz

TiO₂ nanowires with diameters of 2 nm - 3 nm and length up to 100 nm were synthesized via a hydrothermal route. They were characterized by X-Ray diffraction and high resolution transmission electron microscopy (HRTEM). The were found to grow in the TiO₂(B) modification with “b” being the long axis. Subsequently they were impregnated with a 4 M HCl solution containing carrier-free ⁴⁴Ti (t_1/2 = 60 y). After drying the label was diffused into the wires at 180°C for two hours. This temperature is enough to diffuse the label a few lattice spacings. We performed Time Differential Perturbed Angular Correlation (TDPAC) measurements on the daughter ⁴⁴Sc and obtained two discrete signals for the nuclear quadrupole interaction. The prominent one resembles the value obtained for bulk anatase where the minority fraction is ascribed to the probe atoms close to the surface with an assumed OH-termination. Stable suspensions with ⁴⁴Ti-labelled nanoparticles were produced. The measured re-orientation correlation time via TDPAC agrees with the particle size as determined by HRTEM.