Chromium sites in zeolite framework: Chromyl or chromium hydroxyl groups?

Frederik Tielens; Mazharul M. Islam; Gabriella Skara; Frank De Proft; Tetsuya Shishido; Stanislaw Dzwigaj

doi:10.1016/j.micromeso.2012.02.046

Chromium sites in zeolite framework: Chromyl or chromium hydroxyl groups?

Frederik Tielens, Mazharul M. Islam, Gabriella Skara, Frank De Proft, Tetsuya Shishido, Stanislaw Dzwigaj

Department of Chemistry

Research output: Contribution to journal › Article › peer-review

20 Citations (SciVal)

Abstract

A combined experimental and ab initio periodic DFT calculation on the structure and stability of different chromium-substituted zeolite models are presented. Experimental investigation by XRD, FT-IR and UV-vis show the presence of chromium in SiBEA zeolite. The favorable chromium sites are characterized by their calculated geometrical parameters, energetics, vibrational frequencies and protonation/deprotonation energies. The theoretical vibrational frequencies are compared with experimental FT-IR measurements. A phase diagram was constructed on the basis of calculated total energies of the optimized structures. Cr(III) is stabilized in the zeolite framework as a tri-coordinated site. Cr sites are predicted to be more acidic than group V containing zeolites. Dehydration of the site leads to the formation of a Cr(VI) containing a CrO group. These results are fully consistent with experimental data and allow the identification of the molecular structure of chromium sites in a zeolite framework.

Original language	English
Pages (from-to)	66-73
Number of pages	8
Journal	Microporous and Mesoporous Materials
Volume	159
Early online date	11 Apr 2012
DOIs	https://doi.org/10.1016/j.micromeso.2012.02.046
Publication status	Published - 1 Sept 2012

Funding

This work was performed using HPC resources from GENCI-[CCRT/CINES/IDRIS] (Grant 2011-[x2011082022]) and the CCRE of Université Pierre et Marie Curie. Dr. B. Diawara from LCPS ENS Paris is kindly acknowledged for providing us with ModelView used in the visualization of the structures. French-Belgian bilateral PHC Tournesol Project No. 25264TA is acknowledged for financial support.

Keywords

Chromium
DR UV-vis
FT-IR
Periodic DFT
Zeolite

ASJC Scopus subject areas

General Chemistry
General Materials Science
Condensed Matter Physics
Mechanics of Materials

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10.1016/j.micromeso.2012.02.046

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title = "Chromium sites in zeolite framework: Chromyl or chromium hydroxyl groups?",

abstract = "A combined experimental and ab initio periodic DFT calculation on the structure and stability of different chromium-substituted zeolite models are presented. Experimental investigation by XRD, FT-IR and UV-vis show the presence of chromium in SiBEA zeolite. The favorable chromium sites are characterized by their calculated geometrical parameters, energetics, vibrational frequencies and protonation/deprotonation energies. The theoretical vibrational frequencies are compared with experimental FT-IR measurements. A phase diagram was constructed on the basis of calculated total energies of the optimized structures. Cr(III) is stabilized in the zeolite framework as a tri-coordinated site. Cr sites are predicted to be more acidic than group V containing zeolites. Dehydration of the site leads to the formation of a Cr(VI) containing a CrO group. These results are fully consistent with experimental data and allow the identification of the molecular structure of chromium sites in a zeolite framework.",

keywords = "Chromium, DR UV-vis, FT-IR, Periodic DFT, Zeolite",

author = "Frederik Tielens and Islam, \{Mazharul M.\} and Gabriella Skara and \{De Proft\}, Frank and Tetsuya Shishido and Stanislaw Dzwigaj",

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doi = "10.1016/j.micromeso.2012.02.046",

language = "English",

volume = "159",

pages = "66--73",

journal = "Microporous and Mesoporous Materials",

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TY - JOUR

T1 - Chromium sites in zeolite framework

T2 - Chromyl or chromium hydroxyl groups?

AU - Tielens, Frederik

AU - Islam, Mazharul M.

AU - Skara, Gabriella

AU - De Proft, Frank

AU - Shishido, Tetsuya

AU - Dzwigaj, Stanislaw

PY - 2012/9/1

Y1 - 2012/9/1

N2 - A combined experimental and ab initio periodic DFT calculation on the structure and stability of different chromium-substituted zeolite models are presented. Experimental investigation by XRD, FT-IR and UV-vis show the presence of chromium in SiBEA zeolite. The favorable chromium sites are characterized by their calculated geometrical parameters, energetics, vibrational frequencies and protonation/deprotonation energies. The theoretical vibrational frequencies are compared with experimental FT-IR measurements. A phase diagram was constructed on the basis of calculated total energies of the optimized structures. Cr(III) is stabilized in the zeolite framework as a tri-coordinated site. Cr sites are predicted to be more acidic than group V containing zeolites. Dehydration of the site leads to the formation of a Cr(VI) containing a CrO group. These results are fully consistent with experimental data and allow the identification of the molecular structure of chromium sites in a zeolite framework.

AB - A combined experimental and ab initio periodic DFT calculation on the structure and stability of different chromium-substituted zeolite models are presented. Experimental investigation by XRD, FT-IR and UV-vis show the presence of chromium in SiBEA zeolite. The favorable chromium sites are characterized by their calculated geometrical parameters, energetics, vibrational frequencies and protonation/deprotonation energies. The theoretical vibrational frequencies are compared with experimental FT-IR measurements. A phase diagram was constructed on the basis of calculated total energies of the optimized structures. Cr(III) is stabilized in the zeolite framework as a tri-coordinated site. Cr sites are predicted to be more acidic than group V containing zeolites. Dehydration of the site leads to the formation of a Cr(VI) containing a CrO group. These results are fully consistent with experimental data and allow the identification of the molecular structure of chromium sites in a zeolite framework.

KW - Chromium

KW - DR UV-vis

KW - FT-IR

KW - Periodic DFT

KW - Zeolite

UR - https://www.scopus.com/pages/publications/84860816308

U2 - 10.1016/j.micromeso.2012.02.046

DO - 10.1016/j.micromeso.2012.02.046

M3 - Article

AN - SCOPUS:84860816308

SN - 1387-1811

VL - 159

SP - 66

EP - 73

JO - Microporous and Mesoporous Materials

JF - Microporous and Mesoporous Materials

ER -

Chromium sites in zeolite framework: Chromyl or chromium hydroxyl groups?

Abstract

Funding

Keywords

ASJC Scopus subject areas

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