Preparation of spindle-shape silver core-shell particles

Wu, Qing-Song; Caibei, Zhang; Li, Feng

doi:10.1016/j.matlet.2005.07.009

Cited by 24 publications

(16 citation statements)

References 34 publications

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“…40 Although it is possible to produce Ag-deposited SiO 2 and polymer structures, the Ag particles still tend to grow into larger particles (15−60 nm) or thin film coatings. 7,41 This can be further explained through analysis of the crystalline properties of metal nanoparticles by using the X-ray diffraction scattering function. Due to the strong scattering factor of α- particles from support surface, rather than deposited onto the porous structure.…”

Section: Resultsmentioning

confidence: 99%

Molecular Dynamics Study on Metal-Deposited Iron Oxide Nanostructures and Their Gas Adsorption Behavior

Yue

Jiang

2012

J. Phys. Chem. C

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This study presents a comprehensive theoretical and experimental study on the deposition mechanism of precious metal nanoparticles (e.g., Au, Pt, Ag, and Pd) onto iron oxides (e.g., α-FeOOH, α-Fe 2 O 3 , and Fe 3 O 4 ), which can be generated through a hydrothermal synthesis at ambient conditions. By using molecular dynamics (MD) method, the surface interaction energy between metal nanoparticle and iron oxide surface can be quantified. The analysis shows that the total potential energy of the metal nanoparticles decreases significantly when the metal particles are deposited onto porous or defected sites. The interaction is heavily dependent on nanoparticle size, elemental species, and surface structure of the iron oxide (porous or defects). The van der Waals force was found to play a dominant role in the deposition process. The MD simulation shows that the gases (e.g., CO, propene) on such nanocomposites have a lower diffusion coefficient at the Au/Fe 2 O 3 surface and hence enhance catalytic activity, which may help understand the catalytic mechanism of metal oxide nanocomposites.

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Section: Resultsmentioning

confidence: 99%

Molecular Dynamics Study on Metal-Deposited Iron Oxide Nanostructures and Their Gas Adsorption Behavior

Yue

Jiang

2012

J. Phys. Chem. C

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“…Different composite core-shell materials were obtained, such as Ag/C/TiO 2 composites, [74] Ag@TiO 2 nanoparticles [75] and nanowires, [76] Ag@ZrO 2 , [77] reverse SiO 2 /Ag systems, [78] or reverse FeOOH/Ag composites. [79] However, their applications in catalysis are still rather scarce.…”

Section: Silvermentioning

confidence: 99%

Embedded Phases: A Way to Active and Stable Catalysts

et al. 2010

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Industrial catalysts are typically made of nanosized metal particles, carried by a solid support. The extremely small size of the particles maximizes the surface area exposed to the reactant, leading to higher reactivity. Moreover, the higher the number of metal atoms in contact with the support, the better the catalyst performance. In addition, peculiar properties have been observed for some metal/metal oxide particles of critical sizes. However, thermal stability of these nanostructures is limited by their size; smaller the particle size, the lower the thermal stability. The ability to fabricate and control the structure of nanoparticles allows to influence the resulting properties and, ultimately, to design stable catalysts with the desired characteristics. Tuning particle sizes provides the possibility to modulate the catalytic activity. Unique and unexpected properties have been observed by confining/embedding metal nanoparticles in inorganic channels or cavities, which indeed offers new opportunities for the design of advanced catalytic sytems. Innovation in catalyst design is a powerful tool in realizing the goals of more green, efficient and sustainable industrial processes. The present Review focuses on the catalytic performance of noble metal‐ and non precious metal‐based embedded catalysts with respect to traditional impregnated systems. Emphasis is dedicated to the improved thermal stability of these nanostructures compared to conventional systems.

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“…In addition, bimetallic nanoparticles with various shapes, such as NRs [134,135], nanowires [136,137] and spindle-shaped core-shell nanoparticles [138], were also prepared and utilized to increase the SERS activity, similar to that of spherical nanoparticles [102,103].…”

Section: Nanoparticles With Various Shapesmentioning

confidence: 99%

Nanoparticle SERS Substrates

Wang

2010

Surface Enhanced Raman Spectroscopy

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IntroductionSince the discovery that high-intensity Raman scattering of small molecules could be obtained on electrochemical roughened silver surface by Fleischmann et al. [1] in 1974, who attributed the high enhancement to the large number of molecules on the roughened surface, and Jeanmaire et al. 's [2] and Creighton et al.'s [3] independent discovery in 1977 that the enhancement of the Raman scattering is related to an intrinsic surface enhancement effect, marking the beginning of surface-enhanced Raman scattering (SERS) spectroscopy [4], substantial interest has been focussed on the research of the fabrication of SERS-active substrates and on the applications of SERS to many fields, including surface, analytical and life sciences. Meanwhile, investigations of the enhancement mechanisms responsible for the extraordinarily large enhancement of Raman signal of the adsorbate on the roughened metal surfaces have never stopped, and now it is widely accepted that there are two separate mechanisms that describe the overall SERS effect: the electromagnetic effect (EM) and chemical effect (CM). The EM mechanism is based on the interaction of the transition moment of an adsorbed molecule with the electric field of surface plasmons induced by the incoming light on the metal [5-9], which is an effect independent of the probe molecules. For the EM mechanism, the localized surface plasmon resonance (LSPR) plays a key and dominant role in the overall enhancement; whereas the CM is due to the interaction of the adsorbed molecules on the metal with the metal surface, mostly from the first layer of the charge-transfer resonance between the adsorbate and the metal [10-12].More than 30 years have passed since the initial discovery of SERS and the research activity in this field has dramatically increased due to the improvement in techniques resulting from advances in nanotechnology and improved instrumental capabilities. Therefore, SERS has now become a very useful tool in various fields including chemistry, physics and biology. Among these, the basic focus as well as the key step for practical SERS applications is still the successful fabrication of the SERS substrate because the application really depends on the activity and reproducibility of the substrate. The first used SERS substrate was a roughened electrode obtained

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Preparation of spindle-shape silver core-shell particles

Cited by 24 publications

References 34 publications

Molecular Dynamics Study on Metal-Deposited Iron Oxide Nanostructures and Their Gas Adsorption Behavior

Molecular Dynamics Study on Metal-Deposited Iron Oxide Nanostructures and Their Gas Adsorption Behavior

Embedded Phases: A Way to Active and Stable Catalysts

Nanoparticle SERS Substrates

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