Activation of light alkanes on pure and Fe and Al doped silica clusters: A density functional and ONIOM study

Fellah, Mehmet Ferdi
Önal, Işık
C-H bond activation was studied by use of density functional theory (DFT) and ONIOM calculations as implemented in Gaussian 2003 at the B3LYP level utilising 6-31G* as the basis set for Si, Al, and Fe atoms and 3-21G** as the basis set for O and H atoms. Relative energy profiles were determined for pure silica modeled by a Si7O21 cluster and Fe and Al doped silica clusters via coordinate driving calculations. The activation barriers for C-H bond activation of methane and ethane decrease with the substitution of Fe on the silica surface, which theoretically demonstrates a favorable effect of Fe substitution on that surface. The activation energy barriers of methane and ethane are substantially decreased from the approximate transition state values of 55.14 kcal/mol and 54.89 kcal/mol for pure silica cluster to 33.43 kcal/mol and 36.54 kcal/mol obtained for the approximate transition state for Fe substituted silica, respectively.


Investigation of ruthenium-copper bimetallic catalysts for direct epoxidation of propylene: A DFT study
Kizilkaya, Ali Can; Senkan, Selim; Önal, Işık (2010-09-01)
Propylene epoxidation reactions are carried out on Ru-Cu(1 1 1) and Cu(1 1 1) surfaces with periodic density functional theory (DFT) calculations. Ru-Cu(1 1 1) surface is modeled as Cu(1 1 1) monolayer totally covering the Ru(0 0 0 1) surface underneath, in accordance with the literature. It is shown that the Ru-Cu(1 1 1) surface is ineffective for propylene oxide formation since it has a lower energy barrier (0.48 eV) for the stripping of the allylic hydrogen of propylene and a higher energy barrier (0.92 ...
Oxidation of Benzene to Phenol by N2O on an Fe2+-ZSM-5 Cluster: A Density Functional Theory Study
Fellah, Mehmet Ferdi; van Santen, Rutger A.; Önal, Işık (2009-08-27)
Density functional theory (DFT) calculations were carried out in a study of the oxidation of benzene to phenol by N2O on an Fe2+-ZSM-5 cluster. The catalytic cycle has been studied oil a model [Si6Al2O9H14Fe] cluster. It is found that Fe2+ is preferred over Fe1+ as a site for phenol oxidation. A high desorption value of 126.4 kJ/mol suggests that at low temperature phenol desorption is the rate limiting step on the Fe2+-ZSM-5 cluster. It competes with the N2O decomposition step. The computed activation ener...
Effect of magnesium on FOX-7 and its tautomers-A DFT treatment
Türker, Burhan Lemi (2018-06-01)
FOX-7 and its cisoid and transoid 1,5-tautomers as well as magnesium composites of all have been investigated quantum chemically within the restrictions of density functional theory (B3LYP/6-311++G(d,p)). Certain physico-chemical and quantum chemical properties, energies, stabilities, calculated IR and UV-VIS spectra are discussed. The influence of magnesium atom is investigated. It has been found that in FOX-7 composites the magnesium is not a silent ingredient, but interacts with the organic constituents....
A density functional theory study of C-H bond activation of methane on a bridge site of M-O-M-ZSM-5 Clusters (M = Au, Ag, Fe and Cu)
Kurnaz, Emine; Fellah, Mehmet Ferdi; Önal, Işık (2011-02-01)
C-H bond activation of methane on a bridge site M-O-M- of ZSM-5 (M = Au, Ag, Fe and Cu) clusters has been performed by means of Density Functional Theory (DFT) calculations with the utilization of [Si6Al2O9H14(M-O-M](2+) (where M = Au, Ag, Fe and Cu) cluster models representing ZSM-5 surfaces. According to the activation barrier data based on TS calculations. The following activity order of clusters with respect to their activation barriers could be classified: Ag approximate to Au > Cu Fe for Metal-O-Metal...
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...
Citation Formats
M. F. Fellah and I. Önal, “Activation of light alkanes on pure and Fe and Al doped silica clusters: A density functional and ONIOM study,” TURKISH JOURNAL OF CHEMISTRY, pp. 415–426, 2007, Accessed: 00, 2020. [Online]. Available: