Facile synthesis and characterization of TiO2 nanoparticles: X-ray peak profile analysis using Williamson–Hall and Debye–Scherrer methods

Abstract

In this study, TiO2 nanoparticles were synthesized by a sol–gel method involving the interaction of the titanium isopropoxide precursor and sodium hydroxide followed by calcination at a temperature of 450 °C. The effects of stirring time and solution pH on the morphology, phase types and crystallite sizes were investigated. The prepared TiO2 nanoparticles were characterized using X-ray diffraction analysis (XRD), high resolution scanning electron microscopy (HRSEM), high-resolution transmission electron microscopy (HRTEM), selective area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The HRSEM/HRTEM micrograph showed the formation of well distinct TiO2 nanoparticles with spherical shapes except at pH 2. FTIR spectroscopy showed the presence of the Ti–O stretching modes and Ti–O–Ti vibration modes in the samples. Crystallite size and lattice strain at peak broadening of TiO2 nanoparticles were studied using Williamson–Hall analysis and Scherrer’s equation. It was found that W–H crystallite sizes were significantly different from the sizes obtained from Scherrer’s equation at basic medium (pH 8–12) under the applied conditions of stirring time and solution pH for TiO2 nanoparticles. XRD pattern demonstrated the formation of pure anatase phase of TiO2 irrespective of the solution pH and stirring time. XPS analysis showed the existence of the Ti 2p orbital in the oxidation states of + 4. The study demonstrated that stirring time and solution pH determined the crystallite sizes and not the phase types