Transformation from anatase to rutile titania using hydrothermal method: Investigation of morphology and thermal stability

Abstract

Titanium dioxide nanoparticles were successfully synthesized using the hydrothermal method in an autoclave at 100 °C. The onset of the formation of the rutile phase from 400 to 700 °C was investigated through the morphology, structure and thermal properties. X-ray diffractometer and Raman spectroscopy confirmed the formation of a hybrid anatase (A) and rutile (B) phase at 400 °C. The nanoparticles formed spherical structures with an average size between 19.799 and 38.685 nm. Thermogravimetric analysis confirmed that a TiO 2 nanocrystal subjected to higher temperatures undergoes four degradation stages involving the desorption of water molecules, the loss of organic compounds, and the phase change from amorphous to crystalline anatase.

Structure, light absorption properties and photocatalytic activity of carbon-containing titania nanocomposites synthesized via a facile sol–gel method

“…To understand this thermal behavior, DDSC curve was derived, it exhibits 6 transition temperatures over the range from 200 to 650 °C, the 1 st is at 247.2 °C assigned to decomposition of DEA molecules, the 2 nd and 3 rd transition points are at 322.5 and 401.5 °C the second point representing the formation of crystalline anatase and brookite, the formation of Brookite phase is attributed to the decomposition of titanium-organic complexes [ 41 ]. The third transition point represents transition from unstable brookite to stable rutile phase [ 42 , 43 ]. The 4 th transition temperature at 516.1 °C is assigned to decomposition of titanium-organic residues mainly TTIP-DEA complexes and associated species [ 44 ], the 5 th transition point at 570.8 °C may represent oxidation of residual carbon structures and release of CO 2 gas, the last transition point at 604.5 C may represent the removal of oxygen vacancies formed on the surface of due to decarbonization.…”