Synthesis and Characterization of Crystalline and Amorphous Palladium Nanoparticles

Lü, Wei; Wang, Bing; Wang, Kedong; Wang, Xiaoping; Hou, Jian

doi:10.1021/la034160a

Cited by 59 publications

(57 citation statements)

References 37 publications

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“…It was observed that the lower the temperature used, the greater the crystallinity of the nanoparticles. They explained this behavior with the same arguments as Hou et al; 19,20 i.e., low temperatures decrease the reaction rates, which leads to an ordered packing of palladium atoms. However, it is also possible that the chemical nature of the ligand−metal bond changes at different temperatures.…”

Section: ■ Introductionmentioning

confidence: 54%

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: ■ Introductionmentioning

confidence: 54%

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

et al. 2014

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“…In a previous study, we found that Au‐NPs with sizes of ≈3 nm are crystalline 19. However, Lu et al28 recently demonstrated that amorphous palladium‐nanoparticles (Pd‐NPs) can be synthesized. We have studied the crystal structure of the generated Au‐NPs by HR‐TEM and WAXS.…”

Section: Resultsmentioning

confidence: 95%

Mechanism of the Formation of Amorphous Gold Nanoparticles within Spherical Polyelectrolyte Brushes

Schrinner

Polzer

et al. 2007

Macro Chemistry & Physics

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We present a comprehensive investigation on the formation of gold nanoparticles in spherical polyelectrolyte brushes. These colloidal carrier particles consist of a solid polystyrene core onto which long cationic polyelectrolyte chains are grafted. Immersed in water these polyelectrolyte chains can be used to enrich AuCl ions. The metal ions thus confined in the polyelectrolyte layer can be reduced to gold nanoparticles of approximately 1 nm diameter. Cryogenic transmission electron microscopy shows that the Au particles are located near the surface and exhibit a narrow size distribution. Measurements by dynamic light scattering demonstrate that the polyelectrolyte chains are located near the surface of the core particles. This is explained by a crosslinking of the cationic polyelectrolyte chains by the nanoparticles that carry a negative charge. If the Au nanoparticles are removed, the spherical polyelectrolyte brushes re‐expand. High‐resolution electron microscopy together with wide‐angle X‐ray scattering measurements demonstrates that the Au nanoparticles are amorphous. We demonstrate that these Au nanoparticles exhibit catalytic activity for hydrogenation reactions that is slightly below the one of Pt and Pd nanoparticles.magnified image

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“…In general low metal concentrations are employed [4], but also the use of low-boiling organic solvents [5], high temperatures [6], very fast addition of reagents [7], or the use of reagents that are expensive or not commercially available [8] makes their production on an industrial scale difficult.…”

Section: Introductionmentioning

confidence: 99%

BASF NanoSelect™ Technology: Innovative Supported Pd- and Pt-based Catalysts for Selective Hydrogenation Reactions

Witte¹,

Berben²,

Boland³

et al. 2012

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An innovative BASF catalyst manufacturing technology (NanoSelect TM ) is introduced which allows production of heterogeneous catalysts with excellent control over metal crystallite sizes. NanoSelect TM technology enabled the development of Pd catalysts which are leadfree Lindlar catalyst replacements in alkyne-to-cis-alkene hydrogenations. NanoSelect TM Pt catalysts showed excellent chemoselectivity in substituted nitro-arene hydrogenation reactions without build-up of hydroxylamine intermediates. All NanoSelect TM produced catalysts show markedly higher activity per gram of metal leading to tenfold less use of precious metal.

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Synthesis and Characterization of Crystalline and Amorphous Palladium Nanoparticles

Cited by 59 publications

References 37 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

Mechanism of the Formation of Amorphous Gold Nanoparticles within Spherical Polyelectrolyte Brushes

BASF NanoSelect™ Technology: Innovative Supported Pd- and Pt-based Catalysts for Selective Hydrogenation Reactions

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