Catalysis Letters

, Volume 11, Issue 2, pp 209–217 | Cite as

The effects of local structural relaxation on aluminum siting within H-ZSM-5

  • Stephen R. Lonsinger
  • Arup K. Chakraborty
  • Doros N. Theodorou
  • Alexis T. Bell
Article

Abstract

Semiempirical molecular orbital calculations have been performed to study aluminum siting in H-ZSM-5 zeolites. Local structural rearrangements upon substituting aluminum (with a charge compensating proton) for silicon are found to be important. The T12 site is found to be the most preferred site for aluminum substitution. However, the calculated energetics for substitution show that several tetrahedral sites are energetically comparable with regard to aluminum siting. Results pertaining to the electronic properties of the acidic site upon aluminum substitution at each of the twelve distinct tetrahedral sites are presented. The acidic center is found to be a rather soft species, with the HOMO-LUMO energy gap being roughly 8 eV.

Keywords

ZSM-5 molecular orbital theory aluminum siting 

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Copyright information

© J.C. Baltzer A.G. Scientific Publishing Company 1991

Authors and Affiliations

  • Stephen R. Lonsinger
    • 1
  • Arup K. Chakraborty
    • 1
  • Doros N. Theodorou
    • 1
  • Alexis T. Bell
    • 1
  1. 1.Department of Chemical Engineering and Center for Advanced Materials, Lawrence Berkeley LaboratoryUniversity of CaliforniaBerkeleyUSA

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