Catalytic CO Oxidation by O₂ Mediated with Single Gold Atom Doped Titanium Oxide Cluster Anions AuTi₂O_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 AuTi₂O_4–6⁻ clusters, among which AuTi₂O₄⁻ 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 Ti₂O₄ moiety in AuTi₂O₄⁻ 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 Ti₂O₄ moiety drives the direct dissociation of the O₂⁻⋅ unit.