A simple hydrothermal route for the low-temperature processing of nanocrystalline TiO2

Abstract

Well-shaped pure anatase TiO2 nanocrystals were successfully synthesized using an indirect approach by hydrolysis of titanium n-butoxide in 2-propanol, 2-butanol, and 2-pentanol. TiO2 nanocrystals formed without any auxiliary reactants or surfactants at a temperature as low as 200 °C using a simple hydrothermal-assisted sol–gel processing method. The effect of the chain length of alcohol on the degree of crystallinity, particle size, porosity, and pore size was investigated by low-angle and wide-angle X-ray diffraction (XRD), scanning electron microscope, energy-dispersive X-ray, transmission electron microscopy, high-resolution transmission electron microscopy (HR-TEM), selected-area electron diffraction (SAED), and N2 adsorption–desorption analyses. XRD techniques confirmed the crystalline nature and mesostructure of the as-prepared samples. HR-TEM images for the prepared sample in 2-propanol (Ti-1) which is obtained without any calcination show the well-crystallized structure having equilateral hexagonal shape and uniform size. In accordance with XRD data, SAED image shows distinct electron diffraction rings of the set of interplanar distances which could be indexed to the tetragonal phase of TiO2.