On the atomic structure of thiol-protected gold nanoparticles: a combined experimental and theoretical study

Mariscal, Marcelo M.; Olmos-Asar, Jimena A.; Gutiérrez-Wing, C.; Mayoral, Álvaro; Yacamán, Miguel José

doi:10.1039/c004229c

Cited by 43 publications

(46 citation statements)

References 30 publications

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“…16 Results from molecular simulations suggest that the influence of the capping molecule can also reach deeper atomic layers in gold nanoparticles smaller than 2 nm. 17,18 In the case of planar palladium, DFT calculations show that when only thiolates are adsorbed on the surface, there is no reordering of the metal atoms in the first layers; 7,13 however, when sulfide is incorporated as an adsorbate, a considerable surface reconstruction takes place. This behavior is attributed to…”

Section: −14mentioning

confidence: 99%

Influence of Capping on the Atomistic Arrangement in Palladium Nanoparticles at Room Temperature

et al. 2014

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The role that protecting molecules have on the way that palladium atoms arrange themselves in nanoparticles prepared at room temperature was studied by the analysis of aberration-corrected scanning transmission electron microscopy images and atomistic Langevin dynamics simulations. It was found that the arrangement of Pd atoms is less ordered in thiolate-protected nanoparticles than in amine-protected ones. The experimental and theoretical data showed that the disorder in ∼3 nm thiolate-protected particles is promoted by the strong S−Pd bond in the sulfide layer that surrounds the nanoparticles. ■ INTRODUCTIONThe unique properties of thiolate self-assembled monolayers (SAMs) have provoked great interest in these assemblies, especially for their role in the stability and interfacial properties of thiolate-protected noble-metal nanoparticles (NPs).1,2 Gold nanoparticles are among the most studied metal nanoparticles, to the point of being considered the de facto model system in this field of research.3,4 However, some properties of other metals can be very different from those of gold, and the case of palladium is an example that fulfills this statement. For instance, the adsorption of alkanethiols on planar palladium surfaces produces a sulfide layer (with submonolayer coverage) lying at the interface between palladium and thiolate moieties. 5−7Density functional theory (DFT) calculations show that the sulfide layer comes from the S−C bond scission caused by a charge transfer from the palladium d band to antibonding thiolate orbitals. 7 In addition, it was recently shown that the chemical composition of the surface of alkanethiolate-protected palladium nanoparticles is very similar to that of alkanethiolatemodified bulk palladium: Pd(0) cores are surrounded by a submonolayer of sulfide species, which are protected by alkanethiolates. 8−10 Despite the fact that these particles have very interesting properties that can be exploited in catalysis 11 and sensing, 12 their detailed structure has been barely studied. Indeed, even in recent studies, the already known 5,8 chemical nature of the Pd−thiolate interface is ignored. 11−14It is well-known that thiolate species produce a reconstruction of the gold surface both in planar substrates 15 and in nanoparticles. 16 Results from molecular simulations suggest that the influence of the capping molecule can also reach deeper atomic layers in gold nanoparticles smaller than 2 nm. 17,18 In the case of planar palladium, DFT calculations show that when only thiolates are adsorbed on the surface, there is no reordering of the metal atoms in the first layers; 7,13 however, when sulfide is incorporated as an adsorbate, a considerable surface reconstruction takes place. This behavior is attributed to

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Section: −14mentioning

confidence: 99%

Influence of Capping on the Atomistic Arrangement in Palladium Nanoparticles at Room Temperature

et al. 2014

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“…Au-Au distances and isolated Au atoms are observed close to the edges of the particles, irrespective of their size (see Movies S1-S4), while isolated Au atoms are also distributed across the film. Although it is tempting to associate the rough surfaces of some of the particles with the thiol molecules (Mariscal et al, 2010;Luedtke and Landman, 1996;Kaushik and Clancy, 2012), the low atomic numbers of the atoms in the molecules and the high contrast of the C support suggest that they are not readily visible. Fig.…”

Section: Image Simulationmentioning

confidence: 99%

“…In recent years, aberration-corrected HRTEM has been successfully combined with ab initio calculations to study the binding sites and energies of single atoms on graphene (Meyer et al, 2008;Boukhvalov and Katsnelson, 2009;Cretu et al, 2010;Vanin et al, 2010;Zan et al, 2012;Ramasse et al, 2012;Wang et al, 2012aWang et al, , 2012bWang et al, , 2013Hardcastle et al, 2013), Ostwald ripening between mono-and bi-metallic nanoparticles on a-C (Yoshida et al, 2012Alloyeau et al, 2012), the diffusion of metal atoms and clusters on a-C, graphene and C nanotubes (Werner et al, 2005;Wanner et al, 2006;Batson, 2008;Gan et al, 2008;Cretu et al, 2010Cretu et al, , 2012 and the diffusion and etching of clusters on graphene (Booth et al, 2011;Wang et al,2012bWang et al, , 2013. Aberration-corrected HRTEM and density functional theory have also been used to investigate the structures of thiol-protected clusters (Mariscal et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Transmission electron microscopy of thiol-capped Au clusters on C: Structure and electron irradiation effects

Gontard

Dunin-Borkowski

2015

Micron

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“…Finally, temperature was reduced exponentially until it reached 0.5 K, using the Andersen thermostat with a velocity-Verlet algorithm to produce the trajectories. We have used a new interatomic potential, recently developed by Mariscal et al, 28,29 to represent the interaction between various atoms. The force-field is based on a bond-order Morse potential to represent the interaction between CO molecules and the Pd/ Au atoms.…”

Section: Computer Simulation Detailsmentioning

confidence: 99%

Nanoalloying in real time. A high resolution STEM and computer simulation study

et al. 2011

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Bimetallic nanoparticles constitute a promising type of catalysts, mainly because their physical and chemical properties may be tuned by varying their chemical composition, atomic ordering, and size. Today, the design of novel nanocatalysts is possible through a combination of virtual lab simulations on massive parallel computing and modern electron microscopy with picometre resolution on one hand, and the capability of chemical analysis at the atomic scale on the other. In this work we show how the combination of theoretical calculations and characterization can solve some of the paradoxes reported about nanocatalysts: Au-Pd bimetallic nanoparticles. In particular, we demonstrate the key role played by adsorbates, such as carbon monoxide (CO), on the structure of nanoalloys. Our results imply that surface condition of nanoparticles during synthesis is a parameter of paramount importance.

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On the atomic structure of thiol-protected gold nanoparticles: a combined experimental and theoretical study

Cited by 43 publications

References 30 publications

Influence of Capping on the Atomistic Arrangement in Palladium Nanoparticles at Room Temperature

Influence of Capping on the Atomistic Arrangement in Palladium Nanoparticles at Room Temperature

Transmission electron microscopy of thiol-capped Au clusters on C: Structure and electron irradiation effects

Nanoalloying in real time. A high resolution STEM and computer simulation study

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