Synthesis and optical properties of mesostructured titania–surfactant inorganic–organic nanocomposites

Abstract

Titania–surfactant inorganic–organic nanocomposites with wormhole-like framework mesostructure were synthesized based on self-assembly between a neutral amine surfactant (dodecylamine) and a neutral inorganic precursor (tetrabutyl titanate). The prepared nanocomposites were characterized by x-ray diffraction (XRD), Fourier transformed infrared spectra (FTIR) and x-ray photoelectron spectroscopy (XPS). The optical absorption and photoluminescence spectra have been measured. It has been found that TiO2–surfactant inorganic–organic nanocomposites have a significant red shift of the optical absorption band edge in contrast to that of bulk TiO2, and an unusual room temperature photoluminescence (RTPL). The results obtained indicate that the interfacial effect between the titanium dioxide and the surfactant plays an important role in the optical properties.

A credible role of copper oxide on structure of nanocrystalline mesoporous titanium dioxide

“…The anatase phase has a higher photocatalytic and photoelectrical conversion activity than amorphous, rutile and brookite phases. Therefore, mesoporous TiO 2 containing the high crystallization of anatase has attracted much attention due to its high surface area and a passage wide enough for the ingress of reactants and egress of product, which enhances the surface reactions [1][2][3][4].…”

Nanocrystalline TiO2 by three different synthetic approaches: A comparison

“…The synthesis of TiO 2 based mesoporous molecular sieve by using neutral amine surfactants like decylamine and hexadecylamine as templates was earlier reported (Ulagappan and Rao 1996). Earlier attempts to produce stable mesostructure of TiO 2 using dodecylamine as template have failed but resulted in the formation of wormhole like structures which were found to crumble during extraction of the template (Wang et al 2004). There are also some efforts to stabilize the mesoporous network by the addition of 12 wt% sodium chloride solution (Antonelli 1999) or by subsequent insertion of lithium (Lerouse et al 2001) or by chemical vapour deposition (Yoshitake et al 2002) or by microwave induced hydrothermal synthesis (Wang et al 2006).…”

Synthesis, isolation, and redispersion of resorcinarene-capped anatase TiO2 nanoparticles in nonaqueous solvents

“…2b) taken at higher concentration of C 11 -resorcinarene-capped TiO 2 nanoparticles solution rises as steeply as bare TiO 2 nanoparticles solution toward higher energies, indicating that the optical absorption properties for C 11 -resorcinarene-capped TiO 2 semiconductor nanoparticles are parallel to the absorption properties characteristic of the band structure in semiconductor TiO 2 nanoparticles. The optical absorption red-shift induced by surface modification of TiO 2 with several monodentate organic dyes was observed by several authors: Zou et al [27] with stearic acid, Ghosh et al [26] with sodium dodecylbenzenesulfonate-, and Wang et al [25] with dodecylamine-capped TiO 2 particles. The authors attributed the absorption red shift to an intraband surface states that formed by surfactant molecules chemically bound on the TiO 2 surface.…”

“…Unfortunately, however, anatase TiO 2 is a poor visible light absorber as it requires large band gap energy (3.2 eV) for the excitation of electrons from the filled valence band to the vacant conduction band. Therefore, a number of different approaches have been devoted for the enhancement of the photo-response and improvement of the photo-activity of TiO 2 by: (a) doping transition metals or nonmetals into TiO 2 [14][15][16][17]; (b) reducing TiO 2 using hydrogen plasma [18]; and (c) adsorbing metal complexes [19][20][21][22][23] or organic dyes [24][25][26][27][28][29][30][31][32][33][34][35] onto the surfaces of TiO 2 . More or less, all these attempts have enhanced the visible light absorption ability of TiO 2 .…”

“…However, there are very few approaches of surface modification of TiO 2 nanoparticles by organic dyes having long hydrophobic tails, which enable TiO 2 particles to disperse in nonaqueous organic solvents, reported in literature. For instances, Ghosh and Ramakrishnan [26] reported dodecylbenzenesulfonate-capped TiO 2 nanoparticles; Wang et al [25] reported dodecylamine-capped TiO 2 particles; Weller et al [34] reported oleic acid-capped TiO 2 particles. The binding nature of all these dyes is in monodentate fashion.…”