Size, Shape, and Structural Control of Metallic Nanocrystals

Lisiecki, Isabelle

doi:10.1002/chin.200538228

Cited by 5 publications

(10 citation statements)

References 74 publications

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“…Indeed, several colloidal (28)(29)(30) and dendrimer (31) methodologies are already available for making metal particles with well defined sizes in solution. The control of particle shape is more challenging but has also been achieved recently, largely by controlling the concentration ratio of the capping polymer material to the metal cation used during synthesis (32)(33)(34)(35). Tetrahedral, cubic, irregular-prismatic, icosahedral, and cubo-octahedral particles have been produced in this way.…”

mentioning

confidence: 99%

Synthesis of heterogeneous catalysts with well shaped platinum particles to control reaction selectivity

Lee

Morales

Albiter

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

224

173

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Colloidal and sol-gel procedures have been used to prepare heterogeneous catalysts consisting of platinum metal particles with narrow size distributions and well defined shapes dispersed on high-surface-area silica supports. The overall procedure was developed in three stages. First, tetrahedral and cubic colloidal metal particles were prepared in solution by using a procedure derived from that reported by El-Sayed and coworkers [Ahmadi TS, Wang ZL, Green TC, Henglein A, El-Sayed MA (1996) Science 272: 1924 -1926]. This method allowed size and shape to be controlled independently. Next, the colloidal particles were dispersed onto high-surface-area solids. Three approaches were attempted: (i) in situ reduction of the colloidal mixture in the presence of the support, (ii) in situ sol-gel synthesis of the support in the presence of the colloidal particles, and (iii) direct impregnation of the particles onto the support. Finally, the resulting catalysts were activated and tested for the promotion of carbon-carbon doublebond cis-trans isomerization reactions in olefins. Our results indicate that the selectivity of the reaction may be controlled by using supported catalysts with appropriate metal particle shapes. On the basis of their kinetic behavior, catalytic reactions are often classified as either mild or demanding (1-3). Demanding reactions-such as the oxidation of CO, NO, or hydrocarbons; the synthesis of ammonia; and most oil processing conversionsusually require high temperatures and pressures, and involve small concentrations of intermediates similar to those identified under vacuum. The performance of these reactions often depends strongly on the structure of the catalyst used (4, 5). In contrast, mild reactions-in particular, hydrogenations and isomerizations of unsaturated hydrocarbons-take place under less-demanding temperature and pressure conditions. Mild reactions have historically been considered structure-insensitive (6-8), but that conclusion has been drawn from studies on reactivity vs. metal dispersion that used ill-defined supported catalysts (9, 10) and has been questioned by more recent studies using better catalytic models (11). For instance, both experimental (12-14) and theoretical (15) studies on the selective catalytic hydrogenation of CAO bonds in unsaturated aldehydes have suggested that such reactions may be promoted by close-packed (111) surfaces. In another example, the dehydrogenation of cyclohexene was found to be faster on Pt (111) than on Pt (100) single-crystal surfaces (16). Our recent surface-science investigations on the isomerization of unsaturated olefins (17-19) strongly suggest that selectivity toward the formation of the cis isomer may be favored by Pt (111) facets. Additional surfacescience reports on the conversion of alkyl and alkene adsorbates under vacuum conditions (20-25), as well as studies with more realistic model systems (26, 27), point to a potential structure sensitivity in the conversion of other olefins and unsaturated hydrocarbons.These results not only s...

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mentioning

confidence: 99%

Synthesis of heterogeneous catalysts with well shaped platinum particles to control reaction selectivity

Lee

Morales

Albiter

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

224

173

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“…Control of the shape of nanoparticles has also attracted much interest [18,19]. The shape of Au nanoparticles has a profound influence on their optical properties [19][20][21] and the shape of particles also determines the crystal facets present, which influences their catalytic properties [22,23].…”

Section: Synthetic Strategiesmentioning

confidence: 99%

“…A metal salt is reduced with a chemical reducing agent in the presence of capping agents, surfactants or ions and the temperature and concentrations of the species are varied [17,18]. For example, the kinetics of reduction can be controlled by altering either the concentration of the metal salt or the relative rates of nucleation and growth by varying the concentration and identity of a capping agent [17].…”

Section: Synthetic Strategiesmentioning

confidence: 99%

Interfacial Structures and Bonding in Metal-Coated Gold Nanorods

Chantry

Atanasov

Horswell

et al. 2014

Structure and Bonding

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We present a topical review of research in the field of metal-coated gold nanorods. By combining synthetic design strategies with state-of-the art characterisation techniques (particularly aberration-corrected scanning transmission electron microscopy) and molecular dynamic simulations, we demonstrate the potential to gain a fundamental understanding of, and control over, the atomic detail of metalmetal bonding at the interfaces of core-shell nanorods and nanoparticles. This analysis is facilitated by making comparisons between the related bimetallic systems: AuRh, AuPd and AuPt.

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“…Therefore, the liquid phase can contain hydrophilic or hydrophobic compartments of nanometer size prior to the synthesis, which serve as NC templates. The addition of monomers to the growing cluster is naturally terminated once a NC fills the compartment volume, which predetermines a specified distribution of the NC population close to that of nanocompartments [17] (Fig. 5.9).…”

Section: Chemical Synthesismentioning

confidence: 99%

Optical Biosensing Based on Metal and Semiconductor Colloidal Nanocrystals

Comparelli

Curri

Cozzoli

et al. 2003

Nanotechnologies for the Life Sciences

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The sections in this article are Overview Introduction Colloidal Nanocrystals Size‐dependent Optical Properties Chemical Synthesis Nanocrystal Functionalization for Biosensing Surface Capping Exchange Coating with a Silica Shell Surface Modification through Hydrophobic Interactions Optical Techniques Colorimetric Tests Fluorescence Fluorescence Resonance Energy Transfer Fluorescence Lifetime Multiphoton Techniques Metal‐enhanced Fluorescence Surface Plasmon Resonance Surface‐enhanced Resonance Spectroscopy Advantages and Disadvantages of Nanocrystals in Optical Detection Applications Biosensing with Semiconductor Nanocrystals Biosensing with Metallic Nanoparticles Towards Marketing Conclusions

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Size, Shape, and Structural Control of Metallic Nanocrystals

Abstract: For Abstract see ChemInform Abstract in Full Text.

Cited by 5 publications

References 74 publications

Synthesis of heterogeneous catalysts with well shaped platinum particles to control reaction selectivity

Synthesis of heterogeneous catalysts with well shaped platinum particles to control reaction selectivity

Interfacial Structures and Bonding in Metal-Coated Gold Nanorods

Optical Biosensing Based on Metal and Semiconductor Colloidal Nanocrystals

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