Rationally designing mixed Cu-(μ-O)-M (M = Cu, Ag, Zn, Au) centers over zeolite materials with high catalytic activity towards methane activation

The direct conversion of methane to methanol on [Cu(μ-O)M] (M = Cu, Ag, Zn, Au) bimetal centers in ZSM-5 zeolite is investigated using periodic density functional theory for the first time. Some conclusions are drawn: (1) methane activation on [Cu(μ-O)M] (M = Cu, Ag, Zn, Au) in the ZSM-5 zeolite proceeds through radical-like transition states, and the ability for CH activation decreases in the sequence [Cu(μ-O)Ag] > [Cu(μ-O)Au] > [Cu(μ-O)Cu] > [Cu(μ-O)Zn] . (2) There are two factors that can dramatically enhance C-H bond activation: a greater spin density and a less negative charge of the μ-O atom. (3) The angles ∠CuOM play a minor role in the reactivity difference among [CuOM] -ZSM-5 (M = Cu, Ag, Zn, Au). Our findings will provide insight into methane activation for designing highly effective catalysts applied in industrial processes.