Catalytic CO Oxidation by O₂ Mediated with Single Gold Atom Doped Titanium Oxide Cluster Anions AuTi₂ O_4-6

Gas-phase studies on catalytic CO oxidation by O₂ mediated with gold-containing heteronuclear metal oxide clusters are vital to obtain the structure-reactivity relationship of supported gold catalysts, while it is challenging to trigger the reactivity of clusters with closed-shell electronic structure in O₂ activation. Herein, we identified that CO oxidation by O₂ can be catalyzed by the AuTi₂ O_4-6^- clusters, among which AuTi₂ O₄^- with closed-shell electronic structure can effectively activate O₂ . The reactions were characterized by mass spectrometry and quantum chemical calculations. Theoretical calculations showed that in the initial stage of O₂ activation, the Ti₂ O₄ moiety in AuTi₂ O₄^- contributes dominantly to activate O₂ into superoxide (O₂^- ⋅) without participation of the Au atom. In subsequent steps, the intimate charge transfer interaction between Au and the Ti₂ O₄ moiety drives the direct dissociation of the O₂^- ⋅ unit.