Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, People's Republic of China.
J Am Chem Soc. 2014 Oct 8;136(40):14307-13. doi: 10.1021/ja508547z. Epub 2014 Sep 24.
The single gold atom doped aluminum oxide clusters AuAl3O3(+), AuAl3O4(+), and AuAl3O5(+) have been prepared and mass-selected to react with CO, O2, and mixtures of CO and O2 in an ion trap reactor under thermal collision conditions. The reactions have been characterized by mass spectrometry with isotopic substitution ((16)O2 → (18)O2) and density functional theory calculations. The AuAl3O5(+) cluster can oxidize two CO molecules consecutively to form AuAl3O4(+) and then AuAl3O3(+), the latter of which can react with one O2 molecule to regenerate AuAl3O5(+). The AuAl3(16)O3(+) ions interact with a mixture of C(16)O and (18)O2 to produce the fully substituted (18)O species AuAl3(18)O3-5(+), which firmly identifies a catalytic cycle for CO oxidation by O2. The oxidation catalysis is driven by electron cycling primarily through making and breaking a gold-aluminum chemical bond. To the best of our knowledge, this is the first identification of catalytic CO oxidation by O2 mediated with gas-phase cluster catalysts with single-noble-metal atoms, which serves as an important step to understand single-atom catalysis at strictly a molecular level.
已经制备并通过质量选择得到了单个金原子掺杂的氧化铝团簇 AuAl3O3(+)、AuAl3O4(+) 和 AuAl3O5(+)，然后在离子阱反应器中在热碰撞条件下使它们与 CO、O2 以及 CO 和 O2 的混合物反应。通过同位替代 ((16)O2 → (18)O2) 和密度泛函理论计算的质谱法对反应进行了表征。AuAl3O5(+) 团簇可以连续氧化两个 CO 分子，形成 AuAl3O4(+)，然后形成 AuAl3O3(+)，后者可以与一个 O2 分子反应，重新生成 AuAl3O5(+)。AuAl3(16)O3(+) 离子与 C(16)O 和 (18)O2 的混合物相互作用，生成完全取代的 (18)O 物种 AuAl3(18)O3-5(+)，这有力地证明了 O2 介导的 CO 氧化的催化循环。氧化催化主要通过形成和打破金-铝化学键来驱动电子循环。据我们所知，这是首次通过气相团簇催化剂中单贵金属原子来鉴定 O2 介导的催化 CO 氧化，这是在严格的分子水平上理解单原子催化的重要步骤。
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