Methane Activation Mediated by Dual Gold Atoms Doped in Aluminium Oxide Cluster Cations Au2Al2O3 +

摘要

The study of chemical reactions between gold-doped oxide clusters and methane can provide molecular level mechanisms to understand the activity of gold species supported on metal oxides. The role of single gold atom in methane activation has been identified, while the effect of two or more gold atoms is far from clear. By employing mass spectrometry and theoretical calculations, the reactivity of heteronuclear oxide clusters with dual gold atoms (Au2Al2O3 +) toward methane was explored. Three major reaction products with the formation of CH3 *, AuCH2, and Au were observed experimentally. Theoretical calculations indicate that Au2Al2O3 + contains two separate gold atoms and one oxygencentred radical (O*). Two types of mechanisms for methane activation are identified. The reaction initiated by the O* site primarily generates the CH3 * through hydrogen atom abstraction while the reaction starting from the gold site mainly contributes to the generation of AuCH2 and Au via the mechanism of Lewis acid-base pairs. It was revealed that the formation of gold dimer species driven by the aurophilic interaction plays an important role in the second CH bond activation.