C–H bond activation of methane on M- and MO-ZSM-5 (M = Ag, Au, Cu, Rh and Ru) clusters: A density functional theory study

Density functional theory (DFT) calculations were carried out in a study of C–H bond activation of methane on [(SiH3)4AlO4(M, MO)] (where M = Ag, Au, Cu, Rh and Ru) cluster models representing ZSM-5 surfaces. The following activity order of clusters with respect to their activation barriers could be qualitatively classified: Au ≫ Rh > Cu = Ru > Ag for metal-ZSM-5 clusters and Ag > Cu > Au ≫ Rh > Ru for MetalO-ZSM-5 clusters. Therefore, activation barriers based on transition state calculations showed that Ag–O–, Cu–O– and Au–O-ZSM-5 clusters (4, 5, and 9 kcal/mol, respectively) are more active than all the other clusters for C–H bond activation of methane.