Stability and reactivity of active sites for direct benzene oxidation to phenol in Fe/ZSM-5: A comprehensive periodic DFT study

Guanna Li, Evgeny A. Pidko, Rutger A. Van Santen, Zhaochi Feng, Can Li*, Emiel J.M. Hensen

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

74 Citations (Scopus)

Abstract

The stability of isolated extraframework Fe2+ ions in ZSM-5 zeolite and their reactivity in the benzene to phenol oxidation were studied by periodic DFT calculations. Mononuclear iron(II) cations can only be stabilized at very specific exchange sites of ZSM-5 zeolite. Accordingly, iron will be predominantly present as oxygenated/hydroxylated mono- and binuclear iron complexes in Fe/ZSM-5. The reactivity of isolated Fe2+ does not depend on the local coordination environment around iron, whereas the steric constraints imposed by the zeolite lattice are important for the overall catalytic reactivity. [FeO]+, [HOFe(μ-O)FeOH]2+, [Fe(μ-O)2Fe]2+, [Fe(μ-O)Fe]2+ extraframework complexes are also potential sites for benzene activation. The reaction is however not catalytic in these cases because the vacant active site cannot be regenerated. The presence of basic extraframework O ligands in these complexes favors phenol dissociation resulting in the formation of stable grafted phenolate species, and ultimately, to the deactivation of the oxygenated iron complexes.

Original languageEnglish
Pages (from-to)194-206
Number of pages13
JournalJournal of Catalysis
Volume284
Issue number2
DOIs
Publication statusPublished - 1 Dec 2011
Externally publishedYes

Keywords

  • Binuclear sites
  • DFT calculations
  • Direct benzene oxidation
  • Fe/ZSM-5
  • NO dissociation
  • Phenolate
  • Reaction mechanism

Fingerprint

Dive into the research topics of 'Stability and reactivity of active sites for direct benzene oxidation to phenol in Fe/ZSM-5: A comprehensive periodic DFT study'. Together they form a unique fingerprint.

Cite this