Cu-Ni双金属纳米团簇结构与性质的多尺度模拟
发布时间：2018-07-21 20:33
【摘要】：双金属纳米团簇在最近几十年来受到了人们广泛的关注,它具有更为优良的性能与纯的金属纳米团簇相比。因为双金属纳米团簇具有特殊的物理和化学上的性质,所以能够被运用于化工、能源等众多的领域。由于组成双金属纳米团簇的两种原子本身的各项性质不一样,在组成的双金属纳米团簇体系会呈现出多样的变化,这些变化可能拥有一项特殊的能力,正是因为这些特殊结构吸引了很多人的目光,对双金属纳米团簇进行研究具有很重要的实际意义。本论文主要是通过计算研究不同尺度的Cu-Ni双金属纳米团簇并分析其结构和性能,采用的方法有蒙特卡洛模拟(Monte Carlo, MC)、VASP软件、CP2K软件。在结果分析后得出了如下结论：1.对于大体系和小体系的Cu-Ni双金属纳米团簇都进行细致的分析,不论是通过MC计算得到的还是通过CP2K计算得到的Cu-Ni双金属纳米团簇都满足Cu原子优先占据结构的外层位置随着Cu原子含量的增加,首先是顶点位,其次是边位,在次是表面位,最后是内部位置,比较特殊地,对于大体系的正二十面体结构Cu原子占据中心位置要优先于边位,对于小体系的正二十面体结构Cu原子占据中心位置由于表面位。2.使用本课题组自主编写的新型原子对分布函数的软件(Atomic Pair Distribution Function for Bimetallic Clusters, APDFBC)计算出大体系Cu-Ni双金属纳米团簇的新型原子对分布函数并分析第一近邻原子距离并与实验数据进行对比。3.对于大体系的Cu-Ni双金属纳米团簇,我们还用bop软件计算其序参数去分析局部结构,反映出Cu-Ni双金属纳米团簇在800K和1200K下是液相,100K和300K下是固相,500K下是固液相共存。4.用VASP软件计算了CuxNin-x(n=54,55)双金属纳米团簇的性质,发现结构的对称性会影响体系的磁矩,通过分析体系总的态密度(dos)图和单个金属s,p和d轨道的态密度图中的联系。体系的磁性主要是由Ni原子提供,无磁性的Cu原子在体系内部的相互作用下会表现出一定的磁性。
[Abstract]:Bimetallic nanoclusters have attracted much attention in recent decades and have better performance than pure metal nanoclusters. Because bimetallic nanoclusters have special physical and chemical properties, they can be used in many fields such as chemical industry, energy and so on. Because the properties of the two atoms that make up the bimetallic nanoclusters are different, the composition of the bimetallic nanoclusters presents a variety of changes, which may have a particular ability. It is precisely because these special structures have attracted a lot of attention that it is of great practical significance to study bimetallic nanoclusters. In this paper, the structure and properties of Cu-Ni bimetallic nanoclusters with different scales are studied by means of calculation and analysis. The methods used are Monte Carlo simulation (MC) VASP software and CP2K software. After analyzing the results, the following conclusion is drawn: 1. The Cu-Ni bimetallic nanoclusters in both large and small systems are analyzed in detail. The Cu-Ni bimetallic nanoclusters obtained by MC calculation or CP2K calculation all satisfy the Cu atom preferentially occupying the outer layer of the structure with the increase of Cu atom content, the first is the vertex position, the second is the edge position, and the next is the surface position. Finally, the inner position, especially, the central position of the icosahedron structure Cu atom is superior to the edge position for the large system, and for the small system, the surface position of the icosahedron structure Cu atom occupies the center position because of the surface position. The new atomic pair distribution function of Cu-Ni bimetallic clusters has been calculated by Atomic pair Distribution function for (APDFBC), and the first nearest neighbor atomic distance has been analyzed and compared with the experimental data. For Cu-Ni bimetallic nanoclusters in large scale systems, the order parameters of Cu-Ni bimetallic nanoclusters are calculated by bop software to analyze the local structure. It is shown that Cu-Ni bimetallic nanoclusters are liquid-phase at 800K and 1200K and solid-liquid coexisting at 300K at 500K. The properties of CuxNin-x bimetallic nanoclusters are calculated by using vspp software. It is found that the symmetry of the structure affects the magnetic moment of the system. The relationship between the total density of states (dos) diagram of the system and the density of states of single metal sp and d orbitals is analyzed. The magnetic properties of the system are mainly provided by Ni atoms, and the non-magnetic Cu atoms exhibit certain magnetic properties under the interaction within the system.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1
本文编号：2136777
[Abstract]:Bimetallic nanoclusters have attracted much attention in recent decades and have better performance than pure metal nanoclusters. Because bimetallic nanoclusters have special physical and chemical properties, they can be used in many fields such as chemical industry, energy and so on. Because the properties of the two atoms that make up the bimetallic nanoclusters are different, the composition of the bimetallic nanoclusters presents a variety of changes, which may have a particular ability. It is precisely because these special structures have attracted a lot of attention that it is of great practical significance to study bimetallic nanoclusters. In this paper, the structure and properties of Cu-Ni bimetallic nanoclusters with different scales are studied by means of calculation and analysis. The methods used are Monte Carlo simulation (MC) VASP software and CP2K software. After analyzing the results, the following conclusion is drawn: 1. The Cu-Ni bimetallic nanoclusters in both large and small systems are analyzed in detail. The Cu-Ni bimetallic nanoclusters obtained by MC calculation or CP2K calculation all satisfy the Cu atom preferentially occupying the outer layer of the structure with the increase of Cu atom content, the first is the vertex position, the second is the edge position, and the next is the surface position. Finally, the inner position, especially, the central position of the icosahedron structure Cu atom is superior to the edge position for the large system, and for the small system, the surface position of the icosahedron structure Cu atom occupies the center position because of the surface position. The new atomic pair distribution function of Cu-Ni bimetallic clusters has been calculated by Atomic pair Distribution function for (APDFBC), and the first nearest neighbor atomic distance has been analyzed and compared with the experimental data. For Cu-Ni bimetallic nanoclusters in large scale systems, the order parameters of Cu-Ni bimetallic nanoclusters are calculated by bop software to analyze the local structure. It is shown that Cu-Ni bimetallic nanoclusters are liquid-phase at 800K and 1200K and solid-liquid coexisting at 300K at 500K. The properties of CuxNin-x bimetallic nanoclusters are calculated by using vspp software. It is found that the symmetry of the structure affects the magnetic moment of the system. The relationship between the total density of states (dos) diagram of the system and the density of states of single metal sp and d orbitals is analyzed. The magnetic properties of the system are mainly provided by Ni atoms, and the non-magnetic Cu atoms exhibit certain magnetic properties under the interaction within the system.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1
【参考文献】
相关期刊论文 前2条
1 ;Direct Electrodeposition of Cu-Ni-W Alloys for the Liners for Shaped Charges[J];Journal of Materials Science & Technology;2010年05期
2 蒋治良,刘绍璞,陈飒;银原子团簇的共振散射光谱研究[J];贵金属;2001年03期
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