Superatomic and adsorption properties of Ni atom doped Au clusters
Superatomic and adsorption properties of Ni atom doped Au clusters
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Ni原子掺杂Au团簇的超原子性能和吸附性能
DOI：
10.1039/d1cp00589h
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发表时间：
2021
影响因子：
3.3
通讯作者：
Cheng Longjiu
中科院分区：
文献类型：
--
作者：
Liu Qiman;Fan Pei;Hu Yunhu;Wang Fengwu;Cheng Longjiu
由于具有很强的相对论效应，Au团簇呈现出许多不寻常的几何结构。其中，Au7−、Au8和Au9+分别有18个价电子满足胶体模型中的幻数，但这三个非球形团簇不是超原子。一般来说，一个单一的掺杂原子就可以极大地改变Au团簇的结构和电子性质。在这里，我们用遗传算法程序结合密度泛函理论研究了NiAu7−、NiAu8和NiAu9+团簇的结构。结果表明，合金团簇均为三维球状结构。分子轨道和态密度分析表明，它们具有完全填充的超原子壳(1S21P6)，其中Ni原子的电子结构为D10。然后对合金团簇的静电势表面进行了分析，计算结果表明，NiAu8超原子具有显著的σ空穴和正电势区。此外，这些缺电子区域可以被认为是与某些电子给体的相互作用位置。当一个Lewis基CO气体分子被吸附在Au基超原子上后，我们发现C-O键距略有拉长，伸缩频率发生了显著的红移。这是由于NiAu8的Au原子的5d电子向CO分子的反键π轨道转移所致。因此，这是寻找新型超原子和潜在的共价键活化催化剂的有效策略。
Due to their strong relativistic effects, Au clusters exhibit many unusual geometric structures. Among them, Au7−, Au8 and Au9+ have 18 valence electrons satisfying the magic numbers in the jellium model, respectively, but these three non-spherical clusters are not superatoms. In general, a single dopant atom can drastically change the structural and electronic properties of Au clusters. Here, we searched structures of NiAu7−, NiAu8 and NiAu9+ clusters using the genetic algorithm program (GA) combined with density functional theory (DFT). It was found that the alloy clusters are all 3D spherical structures. The molecular orbitals and density of states analysis indicate that they have completely filled superatomic shells (1S21P6), in which the electronic structure of the Ni atom is d10. Then, the electrostatic potential surfaces of the alloy clusters are analyzed, and the calculated results show that the NiAu8 superatom has remarkable σ-holes with positive potential regions. Moreover, these electron-deficient regions can be considered as interaction sites with some electron donors. After a Lewis base CO gas molecule is adsorbed on the Au-based superatom, we found that the C–O bond distance becomes slightly elongated and its stretching frequency presents a significant red-shift. This is due to the fact that 5d electrons of the Au atom of the NiAu8 transfer towards the anti-bond π orbitals of the CO molecule. Hence, this is an effective strategy for finding new types of superatoms and potential catalysts for covalent bond activation.