Alumina aerogel

These porous solids obviously have very high surface areas, and they lend themselves naturally to service in catalysis. Palladium catalysts supported on alumina aerogels have been used successfully to remove CO and NO from automobile exhausts,13 and a V205/Ti02 aerogel is itself a catalyst for the selective reduction of NO to N2 and water by gaseous ammonia.14... 

A series of Chromia-Alumina aerogel catalysts containing different contents of chromium was prepared by autoclave method. The specific areas of the catalysis were measured with Ng at 77°K according to the BET method. Their structural properties were determined from the X ray diffraction patterns recorded on a philips diffractometer PW 1050/70. EPR measurements were performed with a 8ruker ZOO TT spectrometer at 77°K operating in X band. DPPH was used as the g value standard. Kinetic data were obtained in dynamic pyrex microreactor operating at atmospheric pressure as described elsewhere (ref. 3). 

H. Zarrouk, A. Ghorbel, G. M. Pajonk and S. J. Teichner, EPR Investigation of Chromia Alumina Aerogel Catalysts for the Transformation of Isobutane by NO into Methacrylonitrile, Proc. 9 th Ibero Americain Symposium on Catalysis, Lisbon, July 16-21, 1984, pp 339 - 348. 

Mizushima, Y. Hori, M. Alumina aerogel catalysts prepared by two supercritical drying method used in methane combustion. J. Mater. Res. 1996, 31. 

Al-Yassir. N, and le van Mao, R., Catalysts for the thermo-catalytic cracking (TCC) process Interaction between the yttria in yttria-doped alumina aerogel and the mono-oxide MoO,. CeOj, and bi-oxide MofT-CeOj species, Appl. Catal. A, 332, 273, 2007. 

CATALYTIC OXIDATION OF PROPANE OVER PALLADIUM SUPPORTED ON ALUMINA AEROGEL. EFFECTS OF THE PRETREATMENT ON THE ACTIVITY AND INVESTIGATION OF THE STATE OF PALLADIUM BY GRAZING-INCIDENCE-X-RAY DIFFRACTION... 

The present work is concerned with the influence of the pretreatment of an alumina-aerogel supported Pd catalyst on its activity in propane oxidation. The state of Pd and the crystalline state of alumina aerogel were investigated by grazing-incidence X-ray diffraction (GIXD). To our knowledge, this method is applied for the first time to supported metal catalysts. In addition, a comparison of the structural and catalytic oxidation properties of Pd, Pt and Pt-Rh supported on alumina carriers was made. 

The alumina aerogel (490 m2.g-l, 1.3 cm. g-l micro-mesopore volume) was prepared from aluminum sec - butoxide dissolved in sec - butanol by hydrolysis with a stoichiometric amount of water. The alcogel was then dried in an autoclave under supercritical conditions with respect to sec - butanol [4]. Two conventional alumina xerogels ( Degussa 110 m2.g-l and R.P. 100 m2.g-i ) were also used as supports of Pd and Pt-Rli catalysts. 

Figure 22. TbM micrographs ofcogclcd Ni/alumina aerogel catalyst reduced at dilTcreni temperatures (a) 723 K. (b) 823 K and (e) 973 K.

Poco, J.F., Satcher, J.H., Jr., Hrubesh, L.W., 2001, Synthesis of high porosity monolithic alumina aerogel, J. Non-Cryst. Solids 285,57-63. 

Silica and, to a less extent, alumina aerogels are detailed below because most of the catalytic aerogels are silica- or alumina-based composites. As mentioned in the Abstract section, the synthesis of an aerogel results from a two-step process First, a solution-to-sol-to-gel is prepared, and second, this gel is supercritically dried in an autoclave. 

Catalytic Reaction Tests on a 50 wt% Nickel on Alumina Aerogel... 

An example of forming a mesoporous alumina aerogel without reacting an alkoxide as an alumina precursor is described in a paper by Nguyen et al. (27). 

Willey RJ, Lai H, Peri JB (1991) Investigation of iron oxide-chromia-alumina aerogels for the selective catalytic reduction of nitric oxide by ammonia. J Catal 130 319-331... 

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