Location of Mn(II) ions in manganese aluminophosphate molecular sieves: a comparative study of MnAPO-11 and MnAPO-41

Sinha, A. K. ; Satyanarayana, C. V. V. ; Srinivas, D. ; Sivasanker, S. ; Ratnasamy, P. (2000) Location of Mn(II) ions in manganese aluminophosphate molecular sieves: a comparative study of MnAPO-11 and MnAPO-41 Microporous and Mesoporous Materials, 35-36 . pp. 471-481. ISSN 1387-1811

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Official URL: http://www.sciencedirect.com/science/article/pii/S...

Related URL: http://dx.doi.org/10.1016/S1387-1811(99)00243-7

Abstract

Manganese-incorporated aluminophosphate molecular sieves, MnAPO-11, MnAPO-41 and MnSAPO-41, were prepared by hydrothermal methods. The samples were characterized by the techniques of X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric/differential thermal analysis (TGA/DTA), magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy (31P and 27Al) and electron spin resonance (ESR) spectroscopy. Thermal analysis data reveal that complete oxidation of the template takes place at higher temperatures in the manganese-containing samples than in the AlPO4s. The greater difficulty in template removal from manganese-containing samples is attributed to the presence of protonated template ions compensating the negative charge created by manganese present in the framework. ESR studies reveal that a larger fraction of the manganese in AlPO4-11 is present in the framework than in AlPO4-41. At least four different Mn2+ species in both framework and extra-framework positions could be identified in the samples.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Aluminophosphates; ESR; Metal Aluminophosphates; MnAPO-11; MnAPO-41; MnSAPO-41
ID Code:47715
Deposited On:12 Jul 2011 14:38
Last Modified:05 Jul 2012 08:20

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