期刊
ACS NANO
卷 8, 期 7, 页码 7465-7477出版社
AMER CHEMICAL SOC
DOI: 10.1021/nn502767t
关键词
nanoparticles; string collective atomic motion; molecular dynamics; nanoparticle shape fluctuations
类别
资金
- Natural Sciences and Engineering Research Council of Canada
- NIH [1 R01 EB006398-01A1]
Normally chemically inert materials such as Au have been found to be catalytically active in the form of particles whose size is about 1 nm. Direct and indirect observations of various types of metal nanoparticles (NPs) in this size range, under catalytically relevant conditions for fuel-cell operation and catalysis, have indicated that such small particles can exhibit large spontaneous shape fluctuations and significant changes in shape and chemical activity in response to alterations in environmental conditions. NPs also normally exhibit facile coalescence when in proximity, impacting their stability and reactivity in applications. We perform molecular dynamics simulations on Ni nanoparticles, a commonly used NP in catalytic applications and carbon nanotube growth, in the approximate to 1 nm size regime where large-scale shape fluctuations have been observed experimentally. An analysis of the large-gale shape fluctuations observed in our simulations of these small NPs indicates that they are accompanied by collective motion of Ni atoms through the NP center, and we quantify these dynamic structures and their impact on NP shape. In contrast, stringlike collective atomic motion is confined to the NP interfacial region of NPs having a diameter greater than a few nanometers, and correspondingly, the overall NP shape remains roughly spherical, a case studied In our prior Ni NP simulations. Evidently, the large spontaneous NP shape fluctuations reflect a change in character of the collective atomic dynamics when the NPs become critically small in size.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据