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

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.

Graphical AbstractTiO2 scaffolds of anisotropic rutile particles were grown from rutile seeds by using molten salt synthesis techniques. Depending on the morphology of the seed layer, heat treatment temperature, time and salt medium, rutiles were grown in the form of different morphologies and microstructures.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch Highlights► We fabricated rutile scaffolds of different morphologies and microstructures by using a simple two step molten salt synthesis technique on rutile seeds. ► By varying the microstructure of the seeds, the salt medium, and heat treatment, it is possible to grow anisotropic rutile particles of different sizes and aspect ratios. ► Coatings of nano-whiskers (20–50 nm diameter and 0.5–1μm length) were prepared using a mixture of amorphous titanium hydroxide and NaCl–KCl eutectic and a heat treatment of 700 ºC for 5 h. ► Three dimensional platelets (2–5 μm thick, 2–10 μm wide and 5–25 μm long) were prepared from a mixture of amorphous titanium hydroxide and NaCl treated at 850 °C for 20 h.