当前位置: X-MOL 学术Nano Lett. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Local Chemical Ordering and Negative Thermal Expansion in PtNi Alloy Nanoparticles
Nano Letters ( IF 9.6 ) Pub Date : 2017-11-29 00:00:00 , DOI: 10.1021/acs.nanolett.7b04219
Qiang Li 1 , He Zhu 1 , Lirong Zheng 2 , Longlong Fan 1 , Na Wang 1 , Yangchun Rong 1 , Yang Ren 3 , Jun Chen 1 , Jinxia Deng 1 , Xianran Xing 1
Affiliation  

An atomic insight into the local chemical ordering and lattice strain is particular interesting to recent emerging bimetallic nanocatalysts such as PtNi alloys. Here, we reported the atomic distribution, chemical environment, and lattice thermal evolution in full-scale structural description of PtNi alloy nanoparticles (NPs). The different segregation of elements in the well-faceted PtNi nanoparticles is convinced by extended X-ray absorption fine structure (EXAFS). Atomic pair distribution function (PDF) study evidences the coexistence of the face-centered cubic and tetragonal ordering parts in the local environment of PtNi nanoparticles. Further reverse Monte Carlo (RMC) simulation with PDF data obviously exposed the segregation as Ni and Pt in the centers of {111} and {001} facets, respectively. Layer-by-layer statistical analysis up to 6 nm for the local atomic pairs revealed the distribution of local tetragonal ordering on the surface. This local coordination environment facilitates the distribution of heteroatomic Pt–Ni pairs, which plays an important role in the negative thermal expansion of Pt41Ni59 NPs. The present study on PtNi alloy NPs from local short-range coordination to long-range average lattice provides a new perspective on tailoring physical properties in nanomaterials.

中文翻译:

PtNi合金纳米粒子中的局部化学有序化和负热膨胀

对于最近出现的双金属纳米催化剂(例如PtNi合金)而言,对局部化学有序性和晶格应变的原子洞察特别有趣。在这里,我们在PtNi合金纳米颗粒(NPs)的完整结构描述中报告了原子分布,化学环境和晶格热演化。扩展的X射线吸收精细结构(EXAFS)可以说服面面俱全的PtNi纳米颗粒中元素的不同隔离。原子对分布函数(PDF)研究证明了PtNi纳米粒子局部环境中面心立方和四边形有序部分的共存。用PDF数据进行的进一步反向蒙特卡洛(RMC)模拟显然将偏析暴露为{111}和{001}面中心的Ni和Pt。局部原子对的高达6 nm的逐层统计分析显示了表面上局部四边形有序的分布。这种局部配位环境促进了杂原子Pt-Ni对的分布,这在Pt的负热膨胀中起着重要作用41个Ni 59个NP。从局部短程配位到长程平均晶格的PtNi合金NPs的当前研究为定制纳米材料的物理性质提供了新的视角。
更新日期:2017-11-29
down
wechat
bug