Mesoporous titania coatings

Y. Tai, W. Yamaguchi, K. Tajiri, and H. Kageyama, 2009, Structures and CO oxidation activities of size-selected Au nanoparticles in mesoporous titania-coated silica aerogels, Appl. Catal. A 364,143-149... 

The dye-sensitized solar cell (DSC), often called the Gratzel cell, is constructed as follows. A layer of titania paste consisting of anatase nanoparticles is spread onto a glass plate that is coated with a thin conducting layer of fluorine-doped Sn02. The paste contains organic binders that are removed when the film is calcined in air (typically at 450-500 °C), leaving a mesoporous titania film (ca. 10 pm thick) with a porosity of around 50 %. The titania film is immersed in... 

Rebrov, E.V., Berenguer-Murcia, A., Skelton, H.E., Johnson, B.F.G., Wheatley, A.E.H., and Schouten, J.C. (2009) Capillary microreactors wall-coated with mesoporous titania thin film catalyst supports. Lab Chip, 9 (4), 503-506. 

We also include in this class of quasi-2D nanostructured materials Titania deposited inside ordered mesoporous silica (because an inner coating of mesoporous silica may be realized), or nano-dot type Titania particles well dispersed in the ordered porous matrix. We do not consider here solids which contain linear or zig-zag type TiOTiO-nanowires in a microcrystalline porous framework, such as ETS-4 and ETS-10, notwithstanding the interest of these materials also as photocatalysts,146-151 because these nanowires are located inside the host matrix, and not fully accessible from the gas reactants (the reactivity is essentially at pore mouth). 

Amorphous silica has also been mentioned as a starting metal oxide material for the preparation of particulate mesoporous membranes. These membranes were prepared from commercial sols, Ludox (DuPont) or Cecasol (Sobret), and coated on a macroporous a-alumina support [35]. In contrast to crystalline membrane materials such as alumina, titania or zirconia, the evolution of pore size with temperature of amorphous silica membranes was revealed to be more sensitive to drying conditions than to firing temperature (Table 7.1). When heat-treated for several hours at 800°C the silica top layer transformed from an amorphous state to cristobalite. 

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