Monolayer-Protected Bimetal Cluster Synthesis by Core Metal Galvanic Exchange Reaction

Shon, Y.; Dawson, G. Brent; Porter, Marc D.; Murray, Royce W.

doi:10.1021/la025586c

Cited by 92 publications

(84 citation statements)

References 43 publications

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“…Precious metals can be deposited on magnetic nanoparticles through reactions in microemulsion, [137,138] redox transmetalation, [139][140][141] iterative hydroxylamine seeding, [142] or other methods, to protect the cores against oxidation. Cheon et al reported a synthesis of platinum-coated cobalt by refluxing cobalt nanoparticle colloids (ca.…”

Section: Precious-metal Coatingmentioning

confidence: 99%

Magnetic Nanoparticles: Synthesis, Protection, Functionalization, and Application

2007

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This review focuses on the synthesis, protection, functionalization, and application of magnetic nanoparticles, as well as the magnetic properties of nanostructured systems. Substantial progress in the size and shape control of magnetic nanoparticles has been made by developing methods such as co-precipitation, thermal decomposition and/or reduction, micelle synthesis, and hydrothermal synthesis. A major challenge still is protection against corrosion, and therefore suitable protection strategies will be emphasized, for example, surfactant/polymer coating, silica coating and carbon coating of magnetic nanoparticles or embedding them in a matrix/support. Properly protected magnetic nanoparticles can be used as building blocks for the fabrication of various functional systems, and their application in catalysis and biotechnology will be briefly reviewed. Finally, some future trends and perspectives in these research areas will be outlined.

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Section: Precious-metal Coatingmentioning

confidence: 99%

Magnetic Nanoparticles: Synthesis, Protection, Functionalization, and Application

2007

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“…This chemical method has previously been described in detail [7]. To study theoretically the structures of Cu-Au particles, modelling of 38-atom Cu-Au particles has been performed.…”

Section: Methodsmentioning

confidence: 99%

“…2-6 nm sized particles are predominant. Although the capping thiol molecular layers prevent the particles from coalescence in solution [7], particle aggregation may still be observed in during electron microscopy, because the particle concentration is quite high and the capping layers may be vulnerable to the electron beam.…”

Section: Methodsmentioning

confidence: 99%

Truncated-octahedral copper-gold nanoparticles

Tran¹,

Jones²,

Johnston³

et al. 2010

J. Phys.: Conf. Ser.

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Abstract.Observations of the morphology and behaviour of chemically synthesized Cu-Au nanoparticles using high-resolution transmission electron microscopy are described. Truncated-octahedral (TO) particles, which are the result of a morphological evolution induced by the electron irradiation, are found to be the most stable. They have an fcc structure on a large size range of around 1-12 nm. Aggregation of two TO particles, to form a new TO particle, is observed directly under the electron beam. Modelling performed on 38-atom Cu-Au particles using an empirical-potential genetic algorithm also predicts the existence of fcc single-crystal TO structures.

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“…One of the first relevant works involved the preparation of Au, Pt, and Pd nanoparticles by the replacement of Cu or Ag precursors encapsulated in organic dendrimers [55]; the thus-prepared Pt and Pd nanoparticles showed enhanced oxygen reduction electrochemical activity. Examples of other early papers that followed include the preparation of Pt-Co nanoparticles and the exploration of their magnetic properties [56], the preparation of Au-Ag, Pd-Ag, Au-Pd and Au-Cu bimetallic particles with modified plasmonic behavior [57] and the preparation of hollow Pt, Pd, and Au nanostructures using Ag nanoparticle or nanotube templates [58]. Au nanocages prepared by galvanic replacement have also found applications in medicine for targeted cancer therapy and imaging, due to their localized surface plasmon resonance properties that allow heat conversion of Near-infrared (NIR) radiation (see, for example, [59,60]).…”

Section: Nanoparticle and Catalytic Layer Applicationsmentioning

confidence: 99%

Electrocatalysts Prepared by Galvanic Replacement

et al. 2017

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Galvanic replacement is the spontaneous replacement of surface layers of a metal, M, by a more noble metal, M noble , when the former is treated with a solution containing the latter in ionic form, according to the general replacement reaction: nM + mM noble n+ → nM m+ + mM noble. The reaction is driven by the difference in the equilibrium potential of the two metal/metal ion redox couples and, to avoid parasitic cathodic processes such as oxygen reduction and (in some cases) hydrogen evolution too, both oxygen levels and the pH must be optimized. The resulting bimetallic material can in principle have a M noble-rich shell and M-rich core (denoted as M noble (M)) leading to a possible decrease in noble metal loading and the modification of its properties by the underlying metal M. This paper reviews a number of bimetallic or ternary electrocatalytic materials prepared by galvanic replacement for fuel cell, electrolysis and electrosynthesis reactions. These include oxygen reduction, methanol, formic acid and ethanol oxidation, hydrogen evolution and oxidation, oxygen evolution, borohydride oxidation, and halide reduction. Methods for depositing the precursor metal M on the support material (electrodeposition, electroless deposition, photodeposition) as well as the various options for the support are also reviewed. 1. Principle of Galvanic Replacement/Deposition 1.1. Thermodynamic Considerations When a metal, M (e.g., Cu, Fe, Co, Ni, Al, etc.), is immersed in a solution containing ions of a more noble metal, M noble n+ (e.g., Pt, Au, Pd, Ag, Ru, Ir, Rh, Os, etc.-i.e., a metal with a higher standard potential) then, due to the difference in their standard electrochemical potentials, E 0 noble − E 0 > 0, and provided that the ionic form of M is stable under the given experimental conditions (of temperatue, pH, complexing agents etc.), the following reaction is thermodynamically favored and can take place spontaneously: M noble n+ + n/m M → M noble + n/m M m+ (1) This reaction, which bears similarities with transmetalation reactions between metal complexes [1] and is also known as immersion plating [2] in the plating industry and galvanic replacement [3] in materials chemistry, can be considered to originate from the coupling of the following two half-reactions: M noble n+ + ne − ↔ M noble (E 0 noble) (2) M m+ + me − ↔ M (E 0) (3)

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Monolayer-Protected Bimetal Cluster Synthesis by Core Metal Galvanic Exchange Reaction

Cited by 92 publications

References 43 publications

Magnetic Nanoparticles: Synthesis, Protection, Functionalization, and Application

Magnetic Nanoparticles: Synthesis, Protection, Functionalization, and Application

Truncated-octahedral copper-gold nanoparticles

Electrocatalysts Prepared by Galvanic Replacement

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