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Titania applications

An interesting recent example of successful application of the SSG process combined with ensuing supercritical drying is the design of titania-silica mixed oxides for the epoxidation of bulky olefins [16-18]. This example will be used to illustrate the opportunities the combined use of SSG and SCD provide for tailoring the chemical and structural properties of mixed oxides. [Pg.52]

Various other classes of catalysts have been investigated for NH3-SCR, in particular, metal-containing clays and layered materials [43 15] supported on active carbon [46] and micro- and meso-porous materials [31b,47,48], the latter also especially investigated for HC-SCR [25,3lb,48-53], However, while for NH3-SCR, either for stationary or mobile applications, the performances under practical conditions of alternative catalysts to V-W-oxides supported on titania do not justify their commercial use if not for special cases, the identification of a suitable catalyst, or combination of catalysts, for HC-SCR is still a matter of question. In general terms, supported noble metals are preferable for their low-temperature activity, centred typically 200°C. As commented before, low-temperature activity is a critical issue. However, supported noble metals have a quite limited temperature window of operation. [Pg.4]

While vanadia- on titania-based catalysts can be used for both the classes of applications, there are other types of catalysts such as those based on copper [31b], which show good performances in case of mixtures of N0/N02 (nitric acid plants), while performances are worse when applied to emissions from catalytic processes. [Pg.11]

Presently the catalytic selective NOx reduction by ammonia is efficient and widespread through the world for stationary sources. The remarkable beneficial effect of 02 for the complete reduction of NO into nitrogen is usually observed between 200 and 400°C. However, such a technology is not applicable for mobile sources due to the toxicity of ammonia and vanadium, which composes the active phase in vanadia-titania-based catalysts. Main drawbacks related to storing and handling of ammonia as well as changes in the load composition with subsequent ammonia slip considerably affect the reliability of such a process. On the other hand, the use of urea for heavy-duty vehicles is of interest with the in situ formation of ammonia. [Pg.308]

Mohapatra SK, Misra M, Mahajan VK et al (2007) A novel method for the synthesis of titania nanotubes using sonoelectrochemical method and its application for photoelectro-chemical splitting of water. J Catal 246 362-369... [Pg.125]

Topogildis, E., Cass, C.J., Cass, A.E.G. and Durrant, J.R. (2001) Factors that affect protein adsorption on nanostructured titania films A novel spectrochemical application to sensing. Langmuir, 17, 7899—7906. [Pg.266]

Malfatti, L. Falcaro, P Amenitsch, H. Caramori, S. Argazzi, R. Bignozzi, C. A. Enzo, S. Maggini, M. Innocenzi, P. 2006. Mesostructured self-assembled titania films for photovoltaic applications. Microporous Mesoporous Mater. 88 304-311. [Pg.312]

Wang et al240 reported the electrooxidation of MeOH in H2S04 solution using Pd well-dispersed on Ti nanotubes. A similar reaction was studied by Schmuki et al.232 (see above), but using Pt/Ru supported on titania nanotube which appear a preferable catalyst. Only indirect tests (cyclic voltammetry) have been reported and therefore it is difficult to understand the real applicability to direct methanol fuel cell, because several other aspects (three phase boundary to methanol diffusivity, etc.) determines the performance. [Pg.380]

Photobleach mechanism, 19 203 Photobleach reversal grains, 19 201 Photocatalysis, 19 73-106. See also Photocatalysts Photoreactors aqueous pollutants eliminated and mineralized by, 19 89t catalyst modifications in, 19 94-95 catalysts in, 19 75-76 challenges in, 19 101-102 fate of photo-holes in titania, 19 82-85 in fine chemistry applications, 19 102 influence of oxygen pressure in, 19 82 ion doping in, 19 94-95 mass of catalyst in, 19 77-78 noble metal deposit in, 19 94 parameters governing kinetics in, 19 77-82... [Pg.700]

The application of the SEA approach to other systems is straightforward, and involves the three steps (PZC determination, uptake-pH survey, and tuned reduction) demonstrated in the earlier sections. It has recently been suggested that electrostatic adsorption over silanol groups is the cause for metal overexchange in low-aluminum zeohtes [61], It is presently being employed to study noble metal uptake on pure oxides of titania, ceria, zirconia, and niobia. [Pg.187]

To extend the applicability of titania, the ease of production and reproducibility has to be secured in terms of production cost and product quality. The literature is abundant in methodologies to prepare Ti02 photocatalysts, and as a consequence a very large number of materials have been prepared and tested from colloidal to large surface area mesoporous materials. [Pg.435]


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See also in sourсe #XX -- [ Pg.238 ]




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