Titanium dioxide high aspect ratio nanoparticle hydrothermal synthesis optimization

TiO2-B (bronze) nanowires were synthesized via simple hydrothermal treatment of commercial titanium dioxide nanopowder in aqueous NaOH. The reaction temperature, calcination temperature, reaction time, NaOH concentration, autoclave filing fraction and precursor were systematically varied to optimize the nanowire morphology. The crystal structure, morphology and particle size were investigated by XRD, SEM and TEM. The morphology and structure are sensitive to experimental conditions. A reaction temperature of at least 150 degrees C and NaOH concentration at least 10 M are essential, but reaction time from 24 to 72 h makes little difference. Nanowires obtained at 150 degrees C were 60-180 nm wide and 2-4 mu m long, while those after treatment at 200 degrees C were thinner (40-100 nm) and longer (2-6 mu m). The relationship between reaction conditions and morphology is discussed and practical guidelines for titanium dioxide nanowire synthesis are suggested.