Modeling Lewis acidity of transition aluminas by numerical simulations

Journal Article · Thu Jan 01 04:00:00 EST 1998 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.475544· OSTI ID:566998

Alvarez, L J ^[1]; Blumenfeld, A L ^[2]; Fripiat, J J ^[1]

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1. Laboratorio de Simulacion de Materiales, Direccion General de Servicios de Computo Academico, Universidad Nacional Autonoma de Mexico, Insurgentes Sur No. 3000, Zona Cultural, Ciudad Universitaria, Coyoacan 04510, Mexico D. F. (Mexico)
2. Department of Chemistry and Laboratory for Surface Studies, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, Wisconsin 53201 (United States)

The bulk and surface features of an alumina particle obtained by molecular-dynamics simulation are used to support the experimental distribution of aluminums with respect to their coordination number obtained by NMR (nuclear magnetic resonance). This information was obtained by using results of various editing procedures of the {sup 27}Al nuclear magnetic resonance, such as the classical one-pulse (1P) magic angle spinning, the cross polarization (CP) from the protons of chemisorbed ammonia and the 1P or CP rotational echo double resonance (REDOR). Because the REDOR technique revealed that the acid Lewis sites are constituted by pairs of four or fivefold coordinated aluminum atoms about 3 {Angstrom} apart, these pairs were counted in the simulated particle. The agreement with experimental surface density of Lewis sites is satisfactory. {copyright} {ital 1998 American Institute of Physics.}

• OSTI ID: 566998
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 4 Vol. 108; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ALUMINIUM OXIDES
CHEMISORPTION
COORDINATION NUMBER
LEWIS ACIDS
MICROSTRUCTURE
MOLECULAR DYNAMICS METHOD
NMR SPECTRA
PH VALUE
SIMULATION
SURFACE PROPERTIES