TiO2 powders

Infrared absorption spectra have been obtained of methylsilanes bonded to a TIO2 powder. The reacting silanes include He4 nSiXn (n=l-4 X=C1,... 

Gumy. D. et al.. Catalytic activity of commercial of TiO2 powder for the abatement of the bacteria ( coli) under solar simulated light Influence of the isoelectric point, Appl. Catal. B, 63, 76. 2006. 

Titanium dioxide was commercially available (Degussa P-25, surface area 55 m7g). The surface-derivatized TIO2 powder was obtained by treatment with... 

TABLE 6-1. PHYSICAL PROPERTIES OF TIO2 POWDERS (REPRINTED WITH PERMISSION FROM BARRINGER AND BOWEN (1982) www.ceramlcs.org 1982, AMERICAN CERAMIC SOCIETY)... 

Lietti and co-workers studied the kinetics of ammonia adsorption-desorption over V-Ti-O and V-W-Ti-O model catalysts in powder form by transient response methods [37, 52, 53[. Perturbations both in the ammonia concentration at constant temperature in the range 220-400 °C and in the catalyst temperature were imposed. A typical result obtained at 280 °C with a rectangular step feed of ammonia in flowing He over a V2O5-WO3/TiO2 model catalyst followed by its shut off is presented in Figure 13.5. Eventually the catalyst temperature was increased according to a linear schedule in order to complete the desorption of ammonia. 

Figure 2.1 shows the X-ray powder diffraction patterns (CuK ) of compounds TiO, between TijO, (x = 1.5) and TiO2 (x = 2.0). This clearly indicates the convergence of the diffraction patterns to that of TiO2 (rutile) with increasing x, which is why the Magneli school predicted the mother... 

Materials. The titanium dioxide powders were rutile in structure (obtained from the Titanium Division, National Lead Co., Amboy, N. J.), with nominal specific surface areas of 10 and of 100 sq. meters per gram. Chemical analysis by the supplier showed negligible impurities except for 0.8% sodium oxide in the Ti02-100 and traces of iron in both the TiO2-10 and the TiO2-100. The presence of iron was confirmed by the nature of the decay of the neutron irradiation—induced radioactivities. 

Fig. 3.16. CO oxidation on Au/Ti02 powder catalysts prepared by deposition precipitation (from [73]) on the left and on a model catalyst Au/TiO2(110) curve (a), panels (b) and (c) represents band measured by STS and the proportion of particles presenting a bandgap, as a function of particle size (from [74])...

As it appears from the scheme, this process is stoichiometric in light, well different from the above mentioned chain processes. The use of the term photocatalyst in this meaning is not common, since this term is rather referred to the oxidation and mineralization of organic pollutants caused by irradiation in the presence of semiconductor (e.g. TiO2, ZnS, CdS) powders. However, the mechanism in Scheme 4 seems strictly analogous to the usual concept of catalysis, with the additional requirement of photo activation and thus joining the two words and defining the process as photocatalytic seems to us natural, as illustrated in a recent review. ... 

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