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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Au@Hg nanoalloy formation through direct amalgamation: Structural, spectroscopic, and computational evidence for slow nanoscale diffusion
AU - Mertens, S.F.L.
AU - Gara, M.
AU - Sologubenko, A.S.
AU - Mayer, J.
AU - Szidat, S.
AU - Krämer, K.W.
AU - Jacob, T.
AU - Schiffrin, D.J.
AU - Wandlowski, T.
N1 - Cited By :23 Export Date: 17 April 2019 CODEN: AFMDC
PY - 2011
Y1 - 2011
N2 - Dynamic core-shell nanoparticles have received increasing attention in recent years. This paper presents a detailed study of Au-Hg nanoalloys, whose composing elements show a large difference in cohesive energy. A simple method to prepare Au@Hg particles with precise control over the composition up to 15 atom% mercury is introduced, based on reacting a citrate stabilized gold sol with elemental mercury. Transmission electron microscopy shows an increase of particle size with increasing mercury content and, together with X-ray powder diffraction, points towards the presence of a core-shell structure with a gold core surrounded by an Au-Hg solid solution layer. The amalgamation process is described by pseudo-zero-order reaction kinetics, which indicates slow dissolution of mercury in water as the rate determining step, followed by fast scavenging by nanoparticles in solution. Once adsorbed at the surface, slow diffusion of Hg into the particle lattice occurs, to a depth of ca. 3 nm, independent of Hg concentration. Discrete dipole approximation calculations relate the UV-vis spectra to the microscopic details of the nanoalloy structure. Segregation energies and metal distribution in the nanoalloys were modeled by density functional theory calculations. The results indicate slow metal interdiffusion at the nanoscale, which has important implications for synthetic methods aimed at core-shell particles. Interaction of an 11-nm gold hydrosol with metallic mercury leads to Au@Hg particles with up to 15 atom% Hg, following zero-order kinetics. The large difference in cohesive energy between the alloying elements causes slow inward diffusion of Hg over ca. 3 nm, decreasing the coherent face-centered cubic (fcc)-Au lattice length (indicated in red) as observed by X-ray diffraction. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
AB - Dynamic core-shell nanoparticles have received increasing attention in recent years. This paper presents a detailed study of Au-Hg nanoalloys, whose composing elements show a large difference in cohesive energy. A simple method to prepare Au@Hg particles with precise control over the composition up to 15 atom% mercury is introduced, based on reacting a citrate stabilized gold sol with elemental mercury. Transmission electron microscopy shows an increase of particle size with increasing mercury content and, together with X-ray powder diffraction, points towards the presence of a core-shell structure with a gold core surrounded by an Au-Hg solid solution layer. The amalgamation process is described by pseudo-zero-order reaction kinetics, which indicates slow dissolution of mercury in water as the rate determining step, followed by fast scavenging by nanoparticles in solution. Once adsorbed at the surface, slow diffusion of Hg into the particle lattice occurs, to a depth of ca. 3 nm, independent of Hg concentration. Discrete dipole approximation calculations relate the UV-vis spectra to the microscopic details of the nanoalloy structure. Segregation energies and metal distribution in the nanoalloys were modeled by density functional theory calculations. The results indicate slow metal interdiffusion at the nanoscale, which has important implications for synthetic methods aimed at core-shell particles. Interaction of an 11-nm gold hydrosol with metallic mercury leads to Au@Hg particles with up to 15 atom% Hg, following zero-order kinetics. The large difference in cohesive energy between the alloying elements causes slow inward diffusion of Hg over ca. 3 nm, decreasing the coherent face-centered cubic (fcc)-Au lattice length (indicated in red) as observed by X-ray diffraction. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
KW - density functional theory
KW - discrete dipole approximation
KW - gold
KW - mercury
KW - nanoalloys
KW - Amalgamation process
KW - Cohesive energies
KW - Core shell structure
KW - Core-shell nanoparticles
KW - Core-shell particle
KW - Density functional theory calculations
KW - Discrete dipole approximation
KW - Discrete dipole approximation calculations
KW - Elemental mercury
KW - Face-centered cubic
KW - Gold hydrosols
KW - Hg concentrations
KW - Inward diffusion
KW - Lattice length
KW - Mercury content
KW - Metal distributions
KW - Nano scale
KW - Nano-alloys
KW - Particle lattice
KW - Precise control
KW - Rate determining step
KW - Segregation energies
KW - SIMPLE method
KW - Slow diffusion
KW - Synthetic methods
KW - UV-vis spectra
KW - Zero order kinetics
KW - Alloying elements
KW - Density functional theory
KW - Diffraction
KW - Diffusion
KW - Dissolution
KW - Mercury (metal)
KW - Mercury compounds
KW - Metals
KW - Nanoparticles
KW - Nanostructured materials
KW - Nanotechnology
KW - Reaction kinetics
KW - Transmission electron microscopy
KW - X ray diffraction
KW - X ray powder diffraction
KW - Gold
U2 - 10.1002/adfm.201100409
DO - 10.1002/adfm.201100409
M3 - Journal article
VL - 21
SP - 3259
EP - 3267
JO - Advanced Functional Materials
JF - Advanced Functional Materials
SN - 1616-301X
IS - 17
ER -