Nanosize effects in titania based photocatalyst materials

Abstract

Abstract.A review is given of recent work in the authors' laboratory on the characterization of different forms of nanostructured titania. It is shown that nanocrystalline anatase powders and nanocrystalline anatase thin films differ significantly in their optical properties, due primarily to differences in sintering behaviour on drying. It is argued that the electronic properties of these systems are determined by surface phenomena rather than quantum size effects. The novel titanosilicate zeolite ETS-IO which contains one dimensional "quantum wires" of titania provides an alternative system for studying quantum size effects which has considerable potential for photocatalysis.

Mesoporous TiO2/SBA-15, and Cu/TiO2/SBA-15 Composite Photocatalysts for Photoreduction of CO2 to Methanol

“…As mentioned above, the crystallite size of TiO 2 in TiO 2 /SBA-15 composite was increased with the increasing titanium loading whereas the influence of distorted titanium species was decreased with the rising TiO 2 particle size. Thereby, the 45 wt% TiO 2 /SBA-15 and 55 wt% TiO 2 /SBA-15 photocatalysts exhibited a better crystallization and an absorption edge at longer wavelength region approached that of bulk anatase [20].…”

“…As shown in the figure, the absorption edge of mesoporous TiO 2 /SBA-15 shifted to the long-wavelength region with increased titanium content. The UV-Vis spectra of 10 wt% TiO 2 / SBA-15 showed an absorption edge at short wavelength region (330 nm) which was related to the large amount of 5 coordinate titanium species on the surface of nanosized TiO 2 crystallite (1.4 nm, see Table 1) [20]. As mentioned above, the crystallite size of TiO 2 in TiO 2 /SBA-15 composite was increased with the increasing titanium loading whereas the influence of distorted titanium species was decreased with the rising TiO 2 particle size.…”

Industrial synthesis and characterization of nanophotocatalysts materials: titania

“…TiO 2 materials have been synthesized in different shapes and sizes depending on the applications desired [10]. In general, we can define nanophotocatalysts as photoactive materials when the photoactivity can be modulated in the regime of nanometer scale; its means, they have superior efficiency due to its size [11][12][13][14]. The low cost and ready availability give TiO 2 a major advantage over zinc, ceria, and/or other metals based photocatalytic materials.…”

Hydrophilic and optical properties of nanostructured titania prepared by sol–gel dip coating

“…In particular, the possibility of controlling the solar energy absorption, the photocatalytic activity and the surface hydrophilic performances of TiO 2 coatings by tailoring their surface morphology, crystalline structure and the energy gap is an important aim to achieve, in particular for advanced device applications [2,6,8,[11][12][13].…”

“…TiO 2 -based films or powders are of great interest for optical, catalytic, photocatalytic and photovoltaic applications because of their electronic and optoelectronic properties and their high chemical, biological and structural stability [1][2][3][4][5][6][7][8][9][10]. In particular, the possibility of controlling the solar energy absorption, the photocatalytic activity and the surface hydrophilic performances of TiO 2 coatings by tailoring their surface morphology, crystalline structure and the energy gap is an important aim to achieve, in particular for advanced device applications [2,6,8,[11][12][13].…”