Multidimensional thermally-induced transformation of nest-structured complex Au-Fe nanoalloys towards equilibrium  

作　　者：Jacob Johny Oleg Prymak Marius Kamp Florent Calvo Se-Ho Kim Anna Tymoczko Ayman El-Zoka Christoph Rehbock Ulrich Schurmann Baptiste Gault Lorenz Kienle Stephan Barcikowski 

机构地区：[1]Technical Chemistry I and Center for Nanointegration Duisburg-Essen(CENIDE),University of Duisburg-Essen,Essen 45141,Germany [2]Inorganic Chemistry and Center for Nanointegration Duisburg-Essen(CENIDE),University of Duisburg-Essen,Essen 45141,Germany [3]Institute for Materials Science,Synthesis and Real Structure,Kiel University,Kiel 24143,Germany [4]University Grenoble Alpes,CNRS,LiPhy,Grenoble 38000,France [5]Max-Planck-Institut fur Eisenforschurtg GmbH,Diisseldorf40237,Germany [6]Department of Materials,Royal School of Mine,Imperial College London,London SW72AZ,UK

出　　处：《Nano Research》2022年第1期581-592,共12页纳米研究（英文版）

摘　　要：Bimetallic nanoparticles are often superior candidates for a wide range of technological and biomedical applications owing to their enhanced catalytic,optical,and magnetic properties,which are often better than their monometallic counterparts.Most of their properties strongly depend on their chemical composition,crystallographic structure,and phase distribution.However,little is known of how their crystal structure,on the nanoscale,transforms over time at elevated temperatures,even though this knowledge is highly relevant in case nanoparticles are used in,e.g.,high-temperature catalysis.Au-Fe is a promising bimetallic system where the low-cost and magnetic Fe is combined with catalytically active and plasmonic Au.Here,we report on the in s/fi;temporal evolution of the crystalline ordering in Au-Fe nanoparticles,obtained from a modern laser ablation in liquids synthesis.Our in-depth analysis,complemented by dedicated atomistic simulations,includes a detailed structural characterization by X-ray diffraction and transmission electron microscopy as well as atom probe tomography to reveal elemental distributions down to a single atom resolution.We show that the Au-Fe nanoparticles initially exhibit highly complex internal nested nanostructures with a wide range of compositions,phase distributions,and size-depended microstrains.The elevated temperature induces a diffusion-controlled recrystallization and phase merging,resulting in the formation of a single face-centered-cubic ultrastructure in contact with a body-centered cubic phase,which demonstrates the metastability of these structures.Uncovering these unique nanostructures with nested features could be highly attractive from a fundamental viewpoint as they could give further insights into the nanoparticle formation mechanism under non-equilibrium conditions.Furthermore,the in situ evaluation of the crystal structure changes upon heating is potentially relevant for high-temperature process utilization of bimetallic nanoparticles,e.g.,during catalysis.

关 键 词：nanoparticles in situ atom probe tomography diffusion RECRYSTALLIZATION atomistic simulation 

分 类 号：TB383[一般工业技术—材料科学与工程]