Polymeric tungsten carbide nanoclusters: structural evolution, ligand modulation, and assembled nanomaterials
Polymeric tungsten carbide nanoclusters: structural evolution, ligand modulation, and assembled nanomaterials
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聚合碳化钨纳米团簇：结构演化、配体调制和组装纳米材料
DOI：
10.1039/c9nr05613k
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发表时间：
2019-11-14
期刊：
影响因子：
6.7
通讯作者：
Cheng, Shi-Bo
中科院分区：
文献类型：
--
作者：
Li, Jun;Huang, Hai-Cai;Cheng, Shi-Bo
由于超原子在团簇组装纳米材料中的潜在应用，寻找具有可调电子和磁性的新型超原子引起了人们极大的兴趣。采用密度泛函理论（DFT）计算方法，以最近观察到的超原子WC团簇为基本单元构建了更大的聚合物团簇（WC）（n）（n = 2-7），并探讨了它们的结构演化，以了解这些超原子团簇向纳米材料的生长模式.揭示了结构演化中一种不寻常的奇偶模式，其中（WC）（2）单元被认为是基本的结构单元。此外，发现W 4C 4具有立方结构，基于此，CO和PH 3配体被连接到W 4C 4上以检查它们的连接效果。理论计算结果表明，在连接过程中，W 4C 4的电子性质会发生显著的变化。有趣的是，CO和PH 3配体的连续连接强烈增加和降低的电子亲和势（EA）和电离势（IP）的连接的W 4C 4集群，分别导致形成的超卤素和超碱物种具有高磁矩。这里强调的所观察到的配体诱导策略可以作为一种有效的方式来调整团簇的电子和磁性，从而形成新的超原子。最后，通过对W_4C_4团簇固体的几何结构和电子结构的研究，揭示了其特殊的三维立方蜂窝结构和金属性质，其中W的5d结构对金属性质的贡献最大，这可能在电催化领域具有潜在的应用价值。
Seeking novel superatoms with tunable electronic and magnetic properties has attracted much interest due to their potential application in cluster assembly nanomaterials. By employing density functional theory (DFT) calculations, the recently observed superatomic WC cluster was adopted as the basic unit to construct larger polymeric clusters, namely (WC)(n) (n = 2-7), and their structural evolution was explored to understand the growth pattern of these superatomic clusters into nanoscale materials. An unusual odd-even pattern in structural evolution was disclosed, in which the (WC)(2) unit is considered as the basic building block. Moreover, W4C4 is found to possess a cubic structure, based on which the CO and PH3 ligands were attached to examine their ligation effects on W4C4. Theoretical results show that the electronic properties of W4C4 can be dramatically altered during the ligation process. Intriguingly, the continuous attachment of CO and PH3 ligands strongly increases and decreases the electron affinities (EA) and ionization potentials (IP) of the ligated W4C4 clusters, respectively, leading to the formation of superhalogen and superalkali species with high magnetic moments. The observed ligand induced strategy highlighted here could serve as an effective way to tune the electronic and magnetic properties of clusters resulting in the formation of novel superatoms. Finally, studies on the geometrical and electronic structures of the W4C4 cluster solid unveil its special 3-D cubic honeycomb geometry and metallic properties with predominant contribution from the 5d of W, which may have potential applications in electro-catalysis.