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 E., Fellah M. F., ÖNAL I.

MICROPOROUS AND MESOPOROUS MATERIALS, vol.138, pp.68-74, 2011 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 138
  • Publication Date: 2011
  • Doi Number: 10.1016/j.micromeso.2010.09.028
  • Journal Name: MICROPOROUS AND MESOPOROUS MATERIALS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.68-74
  • Keywords: DFT, Methane, C-H bond activation, Metal dimer, ZSM-5, NITROUS-OXIDE DECOMPOSITION, IRON SITES, CATALYTIC-PROPERTIES, ELECTRONIC-STRUCTURE, N2O DECOMPOSITION, PHENOL OXIDATION, ZSM-5 ZEOLITES, BENZENE, EXCHANGE, OXYGEN
  • Middle East Technical University Affiliated: Yes

Abstract

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-ZSM-5 clusters. Activation barriers for C-H bond activation of methane on Au-O-Au- and Ag-O-Ag-ZSM-5 clusters are calculated as 4.83 and 4.79 kcal/mol, respectively. These values are lower than the activation barrier values for C-H bond activation on Cu-O-Cu-ZSM-5 and Fe-O-Fe-ZSM-5 which are 9.69 and 26.30 kcal/mol, respectively. Activation process is exothermic on Au-O-Au-, Cu-O-Cu-, and Fe-O-Fe-ZSM-5 clusters whereas it is endothermic on Ag-O-Ag-ZSM-5 cluster. (C) 2010 Elsevier Inc. All rights reserved.