Synthesis of TiO2 scaffold by a 2 step bi-layer process using a molten salt synthesis technique

Abstract

TiO2 scaffolds of anisotropic rutile particles were grown from rutile seeds by using molten salt synthesis techniques. The rutile seeds were either in the form of a separate layer applied on a substrate or a sintered bulk pellet. Mixtures of amorphous titanium hydroxide and salt applied as coatings on the rutile seeds were heat treated. Depending on the morphology of the seed layer, heat treatment temperature, time and salt medium, rutile was grown with different morphologies and microstructures. For NaCl–KCl eutectic salt mixture and heat treatment at 700 °C for 5 h, nano-whiskers of 20–50 nm diameter and 0.5–1 μm length were obtained. For the NaCl salt sample treated at 850 ºC for 20 h, rutile platelets of 2–5 μm thick, 2–10 μm wide and 5–25 μm in length were produced. X-ray diffraction and Raman scattering were used to identify and characterize the rutile phase of the nanowhiskers.