A DFT Study of Direct Oxidation of Benzene to Phenol by N2O over [Fe(mu-O)Fe](2+) Complexes in ZSM-5 Zeolite

Date

2011-05-19

Author

Fellah, Mehmet Ferdi
Pidko, Evgeny A.
van Santen, Rutger A.
Önal, Işık

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

241
views

0
downloads

Density functional theory (DFT) calculations were carried out in a study of the mechanism of benzene oxidation by N2O to phenol over an extra framework dimeric [FeOFe](2+) species in ZSM-5 zeolite represented by a [Si6Al2O9H14(Fe(mu-O)Fe)] cluster model. The catalytic reactivity of such a binuclear species is compared with that of mononuclear Fe2+ and (FeO)(+) sites in ZSM-5 investigated in our earlier works at the same level of theory (J. Phys. Chem. C 2009, 113, 15307; 2010, 114, 12580). The activation energies for the elementary reaction step involved in the benzene hydroxylation over the binuclear and the mononuclear iron sites are comparable. The major difference in the catalytic behavior of the systems considered is related to the ability of Fe3+-containing sites to promote side reactions leading to the active site deactivation. Regeneration of the active site via the phenol desorption is much less favorable than its dissociation resulting in the formation of very stable grafted phenolate species on both the [Fe(mu-O)Fe](2+) and (FeO)(+) sites. In the case of Fe2+ sites such an alternative reaction path does not exist resulting in their stable catalytic performance. Benzene hydroxylation and phenol formation over the binuclear (Fe(mu-O)Fe)(2+) sites in ZSM-5 are promoted in the presence of water. These computational findings are consistent with the experimental observations and allow their rationalization at the molecular level.

Subject Keywords

Nitrous-oxide decomposition, Density-functional theory, Bridged iron sites, One-step oxidation, Active-sites, Selective oxidation, Dinitrogen monoxide

URI

https://hdl.handle.net/11511/30126

Journal

JOURNAL OF PHYSICAL CHEMISTRY C

DOI

https://doi.org/10.1021/jp201582s

Collections

Graduate School of Natural and Applied Sciences, Article

Suggestions

OpenMETU
Core

A DFT study on the [VO](1+)-ZSM-5 cluster: direct methanol oxidation to formaldehyde by N2O FELLAH, MEHMET FERDİ; Önal, Işık (2013-01-01) The mechanism of direct oxidation of methanol to formaldehyde by N2O has been theoretically investigated by means of density functional theory over an extra framework species in ZSM-5 zeolite represented by a [(SiH3)(4)AlO4](1) [V-O](1+) cluster model. The catalytic reactivity of these species is compared with that of mononuclear (Fe-O)(1+) sites in ZSM-5 investigated in our earlier work at the same level of theory (J. Catal. 2011, 282, 191). The [V-O](1+) site in ZSM-5 zeolite shows an enhanced catalytic a...
A Density Functional Theory Study of Direct Oxidation of Benzene to Phenol by N2O on a [FeO](1+)-ZSM-5 Cluster Fellah, Mehmet Ferdi; Önal, Işık; van Santen, Rutger A. (2010-07-29) Density functional theory calculations were carried out in a study of the oxidation of benzene to phenol by N2O on a model (FeO)(1+)-ZSM-5 cluster: the [(SiH3)(4)AlO4(FeO)] cluster. This cluster models the reactivity of Fe3+ oxidic clusters. Results are to be compared with an earlier study (J. Phys. Chem. C 2009, 113, 15307) on a model Fe2+-ZSM-5 cluster. The true activation energies for the elementary reaction step in which phenol is produced appear to be comparable. The major difference between the two sy...
A quantum chemical study of nitric oxide reduction by ammonia (SCR reaction) on V2O5 catalyst surface

Soyer, Sezen; Uzun, Alper; Senkan, Selim; Önal, Işık (2006-12-15)

The reaction mechanism for the selective catalytic reduction (SCR) of nitric oxide by ammonia on (010) V2O5 surface represented by a V2O9H8 cluster was simulated by means of density functional theory (DFT) calculations performed at B3LYP/6-31G** level. The computations indicated that SCR reaction consisted of three main parts. For the first part, ammonia activation on V2O5 was investigated. Ammonia was adsorbed on Bronsted acidic V-OH site as NH4+ species by a non-activated process with an exothermic relati...
A DFT study on CO oxidation on Pd-4 and Rh-4 clusters and adsorbed Pd and Rh atoms on CeO2 and Ce(0.75)Z(r0.25)O(2) supports for TWC applications Gerceker, Duygu; Önal, Işık (2013-11-15) CO oxidation reaction mechanisms and energetics are examined on adsorbed Pd-4 and Rh-4 clusters and adsorbed Pd and Rh atoms on CeO2 and Ce0.75Zr0.25 O-2 support structures using DFT methods. Activation barriers and TS structures are computed with CI-NEB method. On cluster adsorbed systems, Zr affects CO binding position and O-2 adsorption mode. Energetically, formation of two CO2 molecules without barrier and surface regeneration is possible only on Pd-4-CeO2 surface. With metal atom substituted surfaces, ...
A density functional theory study of oxidation of benzene to phenol by N2O on Fe- and Co-ZSM-5 clusters Fellah, Mehmet Ferdi; Önal, Işık (2009-06-01) Density functional theory (DFT) calculations were carried out in the study of oxidation of benzene to phenol by N2O on relaxed [(SiH3)(4)AlO4M] (where M=Fe, Co) cluster models representing Fe- and Co-ZSM-5 surfaces. The catalytic cycle steps are completed for both Fe-ZSM-5 and Co-ZSM-5 clusters. The general trend of the results that were obtained in terms of activation barriers for the Fe-ZSM-5 cluster is in agreement with the experimental and theoretical literature. It was observed that the phenol formatio...

Citation Formats

M. F. Fellah, E. A. Pidko, R. A. van Santen, and I. Önal, “A DFT Study of Direct Oxidation of Benzene to Phenol by N2O over [Fe(mu-O)Fe](2+) Complexes in ZSM-5 Zeolite,” JOURNAL OF PHYSICAL CHEMISTRY C, pp. 9668–9680, 2011, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/30126.