Direct synthesis and characterization of high titanium-loading hexagonal mesostructured silica thin films
Journal
Journal of Inorganic and Organometallic Polymers and Materials
Journal Volume
13
Journal Issue
3
Pages
131-141
Date Issued
2003
Author(s)
Abstract
High titanium-loading hexagonal mesostructured silica thin films (Ti-HMSTF) have been successfully synthesized by carefully controlling two factors. One is the hydrolysis and condensation reaction of titanium alkoxide and the other is the aging condition of as-made Ti/Si mixed thin films. The former was controlled by adding acetylacetone (AcAc) as a Ti chelating agent. Regarding the latter, aging under a hydrothermal water vapor ambient environment was found to be effective in synthesizing Ti-HMSTFs with well-defined mesostructures. The maximum molar ratio of Ti/Si in the Ti-HMSTF materials attained a value of 0.3 (referred to as Ti-HMSTF-0.3) for the as-made films. These materials were subjected to a specific hydrothermal aging process, which was prepared from a precursor solution containing AcAc with the molar ratio AcAc/Ti = 1. Small angle X-ray diffractometry (SA-XRD) and transmission electron microscopy (TEM) demonstrated that Ti-HMSTF-0.3 had a highly ordered 2-dimensional hexagonal mesostructure. This 2D hexagonal mesostructure was thermally stable even after the removal of the triblock copolymer template by calcination at 450°C for 4 h. Moreover, small amounts of TiO2 anatase nanocrystals with a size of about 3 nm were formed in the calcined Ti-HMSTF-0.3. O(1s) X-ray photoelectron spectroscopy (XPS) analysis indicated that the incorporation of titanium into the HMSTF was through the Si-O-Ti bonds. The Ti(2p) XPS showed that the binding energy of the titanium in HMSTF decreased with increasing Ti loading. © 2003 Plenum Publishing Corporation.
Subjects
Hydrothermal water vapor treatments; Mesoporous materials; TiO2 anatase nanocrystals; Titania/silica mixed thin films; X-ray photo-electron spectroscopy
Other Subjects
silicon dioxide; titanium; titanium dioxide; article; crystal; film; hydrolysis; nanoparticle; reaction analysis; synthesis; transmission electron microscopy; X ray diffraction; X ray photoelectron spectroscopy
Type
journal article