Abstract
Vanadium–silicon heteronuclear oxide cluster cations were prepared by laser ablation of a V/Si mixed sample in an O~2~ background. Reactions of the heteronuclear oxide cations with methane in a fast‐flow reactor were studied with a time‐of‐flight (TOF) mass spectrometer to detect the cluster distribution before and after the reactions. Hydrogen abstraction reactions were identified over stoichiometric cluster cations [(V~2~O~5~)~n~(SiO~2~)~m~]^+^ (n=1, m=1–4; n=2, m=1), and the estimated first‐order rate constants for the reactions were close to that of the homonuclear oxide cluster V~4~O~10~^+^ with methane. Density functional calculations were performed to study the structural, bonding, electronic, and reactivity properties of these stoichiometric oxide clusters. Terminal‐oxygen‐centered radicals (O~t~^.^) were found in all of the stable isomers. These O~t~^.^ radicals are active sites of the clusters in reaction with CH~4~. The O~t~^.^ radicals in [V~2~O~5~(SiO~2~)~1–4~]^+^ clusters are bonded with Si rather than V atoms. All the hydrogen abstraction reactions are favorable both thermodynamically and kinetically. This work reveals the unique properties of metal/nonmetal heteronuclear oxide clusters, and may provide new insights into CH~4~ activation on silica‐supported vanadium oxide catalysts.