Sol−Gel Synthesis and Hydrothermal Processing of Anatase and Rutile Titania Nanocrystals

Abstract

The alkoxide sol-gel synthesis of nanostructured TiO 2 has been studied systematically to examine the processing parameters that control crystallite size and phase. Nonagglomerated, ultrafine anatase particles have been generated by hydrothermally treating the sol-gelderived hydrous oxides. The degree of crystallinity and purity of the synthesized materials could affect their structural evolution during heat treatment. It was found that the 10-nm anatase TiO 2 sample derived by hydrothermal processing at 180 °C underwent neither phase change nor significant grain growth up to 800 °C. Nanocrystalline rutile TiO 2 particles have also been attained via hydrothermal treatment in an acidic medium. They possessed an ultrafine rutile grain size and a high surface area, which could not be achieved via phase transformation from thermal treatment of anatase particles.

LLDPE/TiO2 nanocomposites produced from different crystallite sizes of TiO2 via in situ polymerization

“…This is because the water:alkoxide ratio determines the nature of the sol-gel chemistry and the structural characteristics of the hydrolyzed gel. High water:alkoxide ratios in the reaction medium ensure a more complete hydrolysis of alkoxides, favoring nucleation over particle growth, thus, reducing crystallite sizes of the nano-TiO 2 product [16]. As expected, the specific surface area of the nano-TiO 2 decreased as crystallite size increased.…”

“…Nano-TiO 2 nanoparticles were synthesized via the sol-gel method using Ti(i-OPr) 4 in a solution of water and methanol according to the method described by Wang and Ying [16]. The molar ratio of water:alkoxide varied between 4, 16 and 80 to vary the nano-TiO 2 crystallite size.…”

“…Therefore, to develop a better understanding on the role of nano-TiO 2 in nanocomposites, we need to understand the role of the sizes of nano-TiO 2 crystallites. The synthesis of controlled crystallite size nano-TiO 2 can be performed with a conventional sol-gel method [16]. This technique allows the control of certain of the nanosolid parameters by setting the parameters before gelation takes place and consequently allowing the preparation of tailor-made nanomaterials [17].…”

Magnetic recyclable microcomposite silica-steel core with TiO2 nanocomposite shell photocatalysts for sustainable water purification

“…43 Typically this involves acid hydrolysis of silica and titania precursors, followed by for example, substrate dipping, and a final thermal curing step. 44,45 This approach offers many advantages, including independent scope for fine tuning particle size, 43 pore size, 46 and film hardness, either by variation of the sol-gel synthesis conditions, or by mixing additional particles (such as photocatalytic P25 TiO 2 nanoparticles). 47 In the present study, micron size magnetic steel particles are first encapsulated within a double sol-gel silica host matrix barrier layer to protect against corrosion, as well as help suppress electron-hole recombination and electron-hole transfer between the TiO 2 outer layer and the underlying steel particles .…”

Preparation and Characterization of Nanocrystalline TiO2 Thin Films Prepared By Sol-Gel Spin Coating Method

“…Titania nano particles have received much interest for applications such as optical devices, sensors, and solar cell applications . There are several factors in determining important properties in the performance of TiO 2 for applications such as particle size, crystallinity and the morphology [4][5][6].Many methods have been established for titania synthesis such as sol-gel technique [5], hydrothermal method [6],chemical vapour deposition [7,8], direct oxidation method and others [10]. Among them sol-gel technique is one of the most used method due to its possibility of deriving unique metastable structure at low reaction temperatures and excellent chemical homogeneity [11].…”