Synthesis, characterization and study of the structural change of nanobelts of TiO2 (H2Ti3O7) to nanobelts with anatase, brookite and rutile phases

Abstract

Titanium dioxide (TiO2) is well known for its wide variety of applications, especially for its physicochemical properties, which are affected by changes in the shape and crystal size, and crystalline structure. In this work, the morphological evolution and phase change of TiO2 nanobelts (H2Ti3O7) to nanobelts with anatase, brookite and rutile phases are reported. TiO2 nanobelts (H2Ti3O7) were synthesized from crystalline phases of TiO2 (anatase, brookite, rutile and the commercial material Degussa P25) under alkaline hydrothermal conditions using NaOH. From H2Ti3O7 nanobelts, phase changes to anatase, brookite and rutile were obtained by hydrothermal method using different hydrochloric acid solutions, in which a combination of the HCl concentration, synthesis time and temperature (set at 175 °C) determine the amount and type of each phase as well as its morphological change. The materials were analyzed using the X-ray powder diffraction technique, XRD, scanning electron microscopy, SEM and 2D micro-Raman and infrared FT-IR spectroscopies. The diffractograms and Raman spectra obtained are characteristic of each crystalline phase of TiO2 (anatase, brookite, rutile and their combinations); while SEM showed the morphology and average dimensions of the nanobelts obtained. Additionally, the analysis of the infrared spectra of each of the synthesized materials consistently correlates the changes that occur due to the morphology and the phases present.