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Organic precursor synthesis of mesoporous Al-Mg mixed oxides and hydrotalcites
|Olexandr Melezhyk , Galina Starukh 1, Olena Oranska , Volodymyr Brei|
1. Institute for Sorption and Endoecology Problems of the National Academy of Sciences of Ukraine (ISPE), General Naumov, 13, Kiev 03164, Ukraine
Among the different types of basic oxides studied, hydrotalcites (HT) have been reported as promising catalysts for the fine–chemicals industry. The known methods of HT synthesis demand complex equipment, include time-consuming stages of precipitation, washing and drying and cause ecological problems due to the contamination of waste water with environmentally unfriendly ions.
The new route for Al-Mg oxides synthesis on the basis of Mg and Al organic salts is presented in this communication. Mixed Al-Mg oxides were synthesized by thermal decomposition (600oC) of Al- and Mg- nitrates in presence of citric acid (citrate method) and Al- and Mg- formates (formate method). The HT sample prepared by traditional co-precipitation method was used for a reference. The prepared Al-Mg oxide samples possess mesoporous structure with different pore-size distribution (determined by nitrogen adsorption method).
The hydration of Al-Mg oxides by its immersion in water have been performed to obtain HT samples. The formation of high ordered HT lamellar structure was confirmed by XRD analysis.
Significant decreasing of surface area (SBET) was observed for the reconstructed HT samples. The applying of the ultrasonic treatment under hydration of the Al-Mg mixed oxides has resulted in increasing of SBET to 220 m2/g which one is comparable with SBET values for starting mixed oxides.
The catalytic activity of prepared samples was tested in the thermo programmed reaction of 2-methyl-3-butyn-2-ol decomposition with evaluation of acetone and acetylene. Among all the samples tested, HT prepared by hydration of mixed oxides with ultrasonic treatment shows the higher catalytic activity in this reaction.
Presentation: Poster at E-MRS Fall Meeting 2007, Symposium A, by Galina Starukh
See On-line Journal of E-MRS Fall Meeting 2007
Submitted: 2007-05-08 09:10 Revised: 2009-06-07 00:44