MgO(001)表面吸附对Aun纳米团簇的结构和活性的影响
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- 论文作者：韩清珍 ; 高锦花 ; 江兆潭 ; 温浩
- 英文论文作者：Qing-zhen Han ; Jin-hua Gao ; Zhao-tan Jiang ; Hao Wen ; Institute of Process Engineering ; Chinese Academy of Sciences ; Department of Physics ; Beijing Institute of Technology
- 年：2016
- 作者机构：中国科学院过程工程研究所;北京理工大学理学院;
- 论文关键词：Aun纳米团簇 ; MgO(001)表面 ; 吸附 ; 活性
- 会议召开时间：2016-07-01
- 会议录名称：中国化学会第30届学术年会摘要集-第二十七分会：光化学
- 语种：中文
- 分类号：O647.3;TB383.1
- 学会代码：ZGHY
- 会议名称：中国化学会第30届学术年会-第二十七分会 ; 光化学
- 会议地点：中国辽宁大连
- 主办单位：中国化学会
- 学会名称：中国化学会
- 页数：1
- 文件大小：257k
- 原文格式：D
- 会议级别：全国
摘要
采用密度泛函理论广义梯度(GGA)法对吸附在MgO(001)表面的Aun纳米团簇结构进行了模拟和分析。结果表明,吸附使Aun(n<5)纳米团簇平均键长增加,导致Au原子之间相互作用减弱,催化活性增强;当n≥5时,平均键长的变化基本趋于稳定,其中Au8由于其较高的对称性吸附后平均键长比其邻近团簇的平均键长短。进一步研究表明团簇的自由能和吸附能的二阶差分随原子个数的变化都表现出奇偶震荡,即在原子数为偶数时团簇与MgO表面的相互作用更紧密;而吸附对于Aun纳米团簇内电子结构的影响也很大,由于Au原子和Mg及O原子之间的电子相互作用,使Au团簇的p态轨道明显增强,而外层s态和d态轨道在费米面处的峰值明显减小,催化活性增强,这与前面平均键长的分析结果是一致的。该研究结果为Aun纳米团簇应用于雾霾消除时含氮氧化物的光催化降解提供了理论支持。
The Aun nano clusters adsorption on MgO(001) are calculated and analyzed by generalized gradient method of density functional theory. It can be found that the average bond length of the Aun(n < 5) nano clusters will be increased when Aun adsorbed on MgO(001), implied that the interaction between Aun atoms is reduced and the catalytic activity is enhanced. At the same time. the average bond length of the Aun(n ≥ 5) will change smoothly, and that of the Au8 will become shorter than that of the adjacent clusters because of its high symmetry. Furthermore, It also can be shown that the variation of the free energy and the second-order difference of adsorption-energy are odd-even oscillation along with the change of the atomic number. In additional, the adsorption on MgO(001) will make the P state orbit of Aun become enhanced, while make the outer s and d states orbit in the Fermi surface area become decreased greatly, it will cause the enhance of Aun catalytic activity. The results will provide the theoretical support to the application of Aun nano clusters to the nitrogen photocatalytic degradation.
The Aun nano clusters adsorption on MgO(001) are calculated and analyzed by generalized gradient method of density functional theory. It can be found that the average bond length of the Aun(n < 5) nano clusters will be increased when Aun adsorbed on MgO(001), implied that the interaction between Aun atoms is reduced and the catalytic activity is enhanced. At the same time. the average bond length of the Aun(n ≥ 5) will change smoothly, and that of the Au8 will become shorter than that of the adjacent clusters because of its high symmetry. Furthermore, It also can be shown that the variation of the free energy and the second-order difference of adsorption-energy are odd-even oscillation along with the change of the atomic number. In additional, the adsorption on MgO(001) will make the P state orbit of Aun become enhanced, while make the outer s and d states orbit in the Fermi surface area become decreased greatly, it will cause the enhance of Aun catalytic activity. The results will provide the theoretical support to the application of Aun nano clusters to the nitrogen photocatalytic degradation.
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