Effect of Organic Templates on the Kinetics and Crystallization of Microporous Metal-Substituted Aluminophosphates

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• 作者：Matthew G. O'Brien ; Manuel Sanchez-Sanchez ; Andrew M. Beale ; Dewi W. Lewis ; Gopinathan Sankar ; C. Richard A. Catlow
• 刊名：Journal of Physical Chemistry C
• 出版年：2007
• 出版时间：November 15, 2007
• 年：2007
• 卷：111
• 期：45
• 页码：16951 - 16961
• 全文大小：639K
• 年卷期：v.111,no.45(November 15, 2007)
• ISSN：1932-7455

文摘

The formation of the microporous cobalt-containing aluminophosphate CoAPO-36 (ATS framework),synthesized using three different organic templates, tripropylamine (TPA), N,N-diisopropylisobutylamine(DPBA), and N-ethyldicyclohexylamine (ECHA), has been examined using in situ energy-dispersive X-raydiffraction (EDXRD). These measurements revealed that the type of template can significantly affect the rateof formation, the order being DPBA > ECHA > TPA. This observation is further supported by the measurementof induction times and activation energies (using the Arrhenius equation), which also follow the same trends.Further ex situ crystallographic studies of the as-synthesized materials have then shown that the template canalso alter the size and symmetry of the unit cell of these materials. By combining these results with computational calculations on the size of each template and its packing within a representative section of the framework, we have shown that the bulky nature of the ECHA template is responsible for the changes in the unitcell, while the interaction energies between the template and the framework at different packing levels rationalizethe EDXRD results, showing that the system with the most stable interaction energy will form more rapidly.