New Insights into the Chemistry of Thiolate-Protected Palladium Nanoparticles

Corthey, Gastón; Rubert, Aldo A.; Picone, A. Lorena; Casillas, Gilberto; Giovanetti, Lisandro J.; Ramallo‐López, José M.; Zelaya, Eugenia; Benítez, G.; Requejo, Félix G.; José–Yacamán, Miguel; Salvarezza, Roberto Carlos; Fonticelli, Mariano H.

doi:10.1021/jp301531n

Cited by 66 publications

(98 citation statements)

References 50 publications

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“…All in all, it is remarkable that the Pd@NH 2 R-S-SR NPs showed a distorted or completely amorphous structure even when the total amount of thiolate + sulfide measured was lower than in the case of Pd@S-SR NPs ((sulfide + thiolate):Pd ≈ 0.7:1). 8 This result rules out the possibility that the reaction rate can be responsible for the differences in the crystallinity of the nanoparticles. Also, it strongly supports the idea that the surface chemistry of the nanoparticle affects the arrangement of the atoms in the whole particle.…”

Section: ■ Results and Discussionmentioning

confidence: 78%

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: ■ Results and Discussionmentioning

confidence: 78%

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

et al. 2014

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“…The recent discovery by Cothey et al regarding the presence of a submonolayer of sulfide species on PdNPs generated from alkanethiols is interesting and could be important for our studies as well. 49 We are currently investigating whether or not PdNPs generated from alkylthiosulfate contain a PdS x layer and will report the results in a future manuscript.…”

Section: Resultsmentioning

confidence: 99%

Controlling Surface Ligand Density and Core Size of Alkanethiolate-Capped Pd Nanoparticles and Their Effects on Catalysis

2012

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This article presents systematic investigations on the relationship between the catalytic property and the surface ligand density/core size of thiolate ligand-capped Pd nanoparticles (PdNPs). The systematic variations in the two-phase synthesis of PdNPs generated from sodium S-dodecylthiosulfate were performed. The resulting PdNPs were characterized by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and 1H NMR and UV–vis spectroscopy. The decrease in the molar equivalent of sodium S-dodecylthiosulfate (Bunte salts) resulted in the formation of nanoparticles with lower surface ligand density and larger particle core size. A decrease in the molar equivalent of tetra-n-octylammonium bromide or an increase in reaction temperature generated nanoparticles with higher surface ligand density and smaller particle core size. As the molar equivalent of NaBH4 decreased, the particle core size increased. The catalysis studies on various PdNPs with different surface ligand density and average core size showed a strong correlation between the PdNP composition and the turnover frequency (TOF) of the isomerization of allyl alcohol. Optimized “good” PdNPs with lower surface ligand coverage and larger core size catalyzed the isomerization of various allyl alcohols to carbonyl analogues with high activity and selectivity.

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“…Other structures found in palladium include single twinned, icosahedral, and decahedral configurations, but in most of the cases it is strictly necessary to add surfactants and coating agents to direct and stabilize the final structure. The coating or structure-stabilizing agents directly influence the atomic arrangement and stability of small Pd particles; particularly, the amine-protected Pd nanoparticles result in well-defined and more stable structures compared to the thiol-protected particles [3,41]. Our results correlated with the formation of well-defined stable configurations and crystalline fcc Pd particles.…”

Section: Molecular Binding Simulation Vp6-pd(ii)mentioning

confidence: 53%

“…To fully exploit the potential of Pd-based nanomaterials, it is necessary to obtain preparations with high control over their size and shape, monodispersion and stability. Different chemical or electrochemical routes have been explored to produce Pd particles, using different stabilizing agents: thiol-based, phosphine ligands, amine-terminated ligands, carbon nanotubes, graphite, polymers (PVP, PVA, PEG), and dendrimers [2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Molecular Docking and Aberration-Corrected STEM of Palladium Nanoparticles on Viral Templates

Carreño-Fuentes¹,

Bahena

Palomares³

et al. 2016

Metals

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Viral templates are highly versatile biotemplates used for the synthesis of nanostructured materials. Rotavirus VP6 self-assembles into nanotubular hollow structures with well-defined diameters and variable lengths, serving as a nucleic acid-free biotemplate to synthesize metal nanoparticles of controlled size, shape, and orientation. Molecular docking simulations show that exposed residues (H173-S240-D242 and N200-N310) of VP6 have the ability to specifically bind Pd(II) ions, which serve as nucleation sites for the growth and stabilization of palladium nanoclusters. Using VP6 nanotubes as biotemplates allows for obtaining small Pd particles of 1-5 nm in diameter. Advanced electron microscopy imaging and characterization through ultra-high-resolution field-emission scanning electron microscopy (UHR-FE-SEM) and spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM) at a low voltage dose (80 kV) reveals, with high spatial resolution, the structure of Pd nanoparticles attached to the macromolecular biotemplates.

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New Insights into the Chemistry of Thiolate-Protected Palladium Nanoparticles

Cited by 66 publications

References 50 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

Controlling Surface Ligand Density and Core Size of Alkanethiolate-Capped Pd Nanoparticles and Their Effects on Catalysis

Molecular Docking and Aberration-Corrected STEM of Palladium Nanoparticles on Viral Templates

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