A van der Waals Density Functional Investigation on the Improved Adsorption Properties of NO on the Rhn/MgO (100) Interface.
A van der Waals Density Functional Investigation on the Improved Adsorption Properties of NO on the Rhn/MgO (100) Interface.
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DOI：
10.1021/acsami.5b05264
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发表时间：
2015-07
影响因子：
9.5
通讯作者：
Guoli Zhou;Pan Li;Z. Tian;Ying Liu
中科院分区：
文献类型：
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作者：
Guoli Zhou;Pan Li;Z. Tian;Ying Liu
采用自旋极化密度泛函理论计算方法，研究了小团簇Rhn（n≤5）在MgO（100）表面上的相互作用和形态，以及Rhn/MgO体系对NO分子的捕获能力.我们发现由于O 2 p和Rh 4d轨道的杂化，Rhn团簇可以紧密地附着在MgO（100）表面上.每个吸附的Rhn簇的最具能量优势的结构看起来类似于孤立的簇的结构，除了靠近衬底的基边缘的长度增加。我们发现，Rhn/MgO系统表现出更强的能力，特别是Rh 2和Rh 4团簇，比裸Rhn团簇。N2 p和Rh 4d轨道的杂化是NO在Rhn/MgO上强吸附的原因。这可以解释为增加的Rh-Rh键长导致有效配位数减少，以及从衬底获得的额外电子的存在，导致N和O原子与Rh原子强烈键合，这反过来又削弱了N-O分子相互作用。此外，结合到NO诱导减少的Rhn/MgO系统的总磁矩。因此，将Rhn置于MgO（100）表面上可以减少成键和磁性之间的竞争。然而，它是否可以改善NO的捕获值得进一步研究。
Using spin-polarized density functional theory calculations, we have studied the interaction and morphology of small Rhn clusters (n≤5) deposited on a MgO (100) surface, as well as the ability of Rhn/MgO systems to trap NO molecules. We show that Rhn clusters can tightly adhere to a MgO (100) surface because of hybridization of O 2p and Rh 4d orbitals. The most energetically preferred structure for each adsorbed Rhn cluster looks similar to the structure of the isolated cluster, except for an increment in the length of base edge(s) close to the substrate. We find that the Rhn/MgO system exhibits a much stronger ability to trap NO, especially for Rh2 and Rh4 clusters, than do the bare Rhn clusters. The hybridization of N 2p and Rh 4d orbitals is responsible for the strong adsorption of NO on Rhn/MgO. This can be explained by the increased Rh-Rh bond length that results in a decrease in the effective coordination number, and the presence of extra electrons obtained from the substrate, causing the N and O atoms to bond strongly to the Rh atoms, which in turn weakens the N-O molecular interaction. Additionally, binding to NO induces a reduction in the total magnetic moment of the Rhn/MgO system. Thus, putting Rhn on the MgO (100) surface can decrease competition between bonding and magnetism. However, whether it can be related to improve trapping of NO deserves further investigations.