Acetylene cyclotrimerization on supported size-selected Pdn clusters (1≤n≤30):: one atom is enough!
Acetylene cyclotrimerization on supported size-selected Pdn clusters (1≤n≤30):: one atom is enough!
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DOI：
10.1021/ja9922476
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发表时间：
2000-04-12
影响因子：
15
通讯作者：
Rösch, N
中科院分区：
文献类型：
--
作者：
Abbet, S;Sanchez, A;Rösch, N
本文用热脱附和傅里叶变换红外光谱研究了乙炔在MgO（100）薄膜上负载的尺寸选择性Pd原子簇（1 ≤ n ≤ 30）上的环三聚反应。令人惊讶的是，苯的生产已经观察到在一个单一的钯原子在低温（300 K）。使用密度泛函理论（DFT）的计算，我们表明，自由的惰性钯原子被激活的电荷转移从缺陷的MgO基板上沉积。对于较大的团簇（7小于或等于n小于或等于30），在430 K的温度下还产生苯，我们的结果表明，对于这种高温反应机制，存在七个钯原子的临界系综。
We studied the cyclotrimerization of acetylene on size-selected Pd, clusters (1 less than or equal to n less than or equal to 30) supported on thin MgO(100) films by thermal desorption and Fourier transform infrared spectroscopy. Surprisingly, the production of benzene is already observed on a single palladium atom at low temperature (300 K). Using density functional theory (DFT) calculations we show that free inert Pd atoms are activated by charge transfer from defect sites of the MgO substrate upon deposition. For larger clusters (7 less than or equal to n less than or equal to 30) benzene is additionally produced at a temperature of 430 K and our results suggest the existence of a critical ensemble of seven palladium atoms for this high-temperature reaction mechanism.