Ligand-stabilized metal clusters and colloids: properties and applications

Schmid, Günter; Maihack, V.; Lantermann, Frank; Peschel, Stefanie

doi:10.1039/dt9960000589

Cited by 158 publications

(87 citation statements)

References 15 publications

(1 reference statement)

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“…1.5) [25][26][27][28][29]. Palladium(II) acetate can be reduced in acetic acid solution by 1 atom hydrogen at room temperature with 2,2 -bipyridine or 1,10-phenanthroline, followed by O 2 treatment [26].…”

Section: Stabilized By Bipyridyl Ligandsmentioning

confidence: 99%

Nanohybridized Synthesis of Metal Nanoparticles and Their Organization

Naka

Chujo

2009

Nanohybridization of Organic-Inorganic Materials

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Metal nanoparticles have various unusual chemical and physical properties compared with those of metal atoms or bulk metal due to the quantum size effect and their large superficial area, which make them attractive for applications such as optics, electronics, catalysis, and biology [1,2]. The catalytic properties of metal nanoparticles have generated great interest over the past decade. Among various metal nanoparticles, gold nanoparticles have tremendously high molar absorptivity in the visible region. Particle aggregation results in further color changes of gold nanoparticles solutions due to mutually induced dipoles that depend on interparticle distance and aggregate size. This phenomenon can be applied to various sensing systems [3][4][5][6][7]. The assembly of gold, silver, or copper nanoparticle monolayers is one of the ideal substrate for surfaced-enhanced Raman scattering (SERS) [8,9].Bare metal nanoparticles are prepared by employing physical methods such as mechanic subdivision of metallic aggregates and evaporation of a metal in a vacuum by resistive heating or laser ablation. Chemical methods such as the reduction of metal salts in solution are the most convenient ways to control the size of the particles and modified the surface chemical composition. To exploit nanoparticle properties for future device fabrication, self-organization of nanoparticles in a controlled manner is required. To construct such devices, new fabrication techniques must be developed with suitable metal nanoparticle-based building blocks. Several patterns for self-assemblies of the metal nanoparticles are schematically illustrated in Fig. 1.1. A number of outstanding reviews on the synthesis and assembly of metal nanoparticle-based building blocks have appeared [2,10]. This chapter highlights recent fabrication techniques of hybrid metal nanoparticles by controlled self-organization of the metal nanoparticle-based building blocks. Design of nanoparticle hybrids will be first focused on using building blocks for further assemblies. Several recent efforts have been concentrated on a system that

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Section: Stabilized By Bipyridyl Ligandsmentioning

confidence: 99%

Nanohybridized Synthesis of Metal Nanoparticles and Their Organization

Naka

Chujo

2009

Nanohybridization of Organic-Inorganic Materials

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“…In anticipation of the covering with silica we investigated two stabilising agents: DPTES and PVP. The ability of the phosphine moiety of DPTES to bind to noble metals is well documented [26,27]. The use of DPTES modifies the surface of the particles such that silanol groups are exposed.…”

Section: Platinum Colloidsmentioning

confidence: 99%

Design of Colloidal Pt Catalysts Encapsulated by Silica Nano Membranes for Enhanced Stability in H2S Streams

et al. 2010

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Poisoning of platinum catalysts by sulphur compounds is a significant problem that prevents their application in untreated gas streams. We introduce a novel concept to circumvent the poisoning problem by encapsulating individual platinum nano-particles with silica layers that act as selective membranes. Greatly enhanced sulfur tolerance for sufficiently dense illustrates the potential of our approach to design noble metal catalysts that survive in sulphur containing gas streams.

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“…Typically nanoparticles provide highly active centers which are not in a thermodynamically stable state due to their high surface energies (Schmid et al, 1996;Doyle et al, 2003). Soluble organic polymers are widely employed supports for synthesizing metal NPs because of their availability and enhanced stabilization properties (Toshima et al, 1991).…”

Section: Introductionmentioning

confidence: 99%

Tunable synthesis of platinum nanoparticles by EtOH reduction in presence of poly (vinylpyrrolidone)

Rahman

Akhter²,

Ahmed

et al. 2015

Bangladesh J. Sci. Ind. Res.

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Monodispersed platinum nanoparticles (Pt-NPs) with an average diameter dTEM 3.1±1.0 nm were synthesized by EtOH reduction method in the presence of an organic polymer poly (vinylpyrrolidone) (PVP) with an average molecular weight of 40,000. Using this particles as seed, size tunable Pt-NPs of d TEM 3.1±1.0 nm to 5.7±1.6 nm with sufficient monodispersity were synthesized by multiple step seeding growth. Formation of Pt-NPs was confirmed by the UV-visible absorption spectra. Transmission electron micrographs (TEM) and powder X-ray diffraction (XRD) patterns confirmed that the particles were single crystalline with fcc crystal geometry.Key words: Platinum; EtOH; Nanoparticles; PVP; Synthesis Available online at www.banglajol.info Bangladesh J. Sci. Ind. Res. 50(2), [87][88][89][90][91][92] 2015 *Corresponding author: E-mail: smjakir080@yahoo.com Chemical syntheses offer a versatile route allowing tailoring of the properties of materials by assembling atoms and particles from the atomic or molecular state to the macroscopic scale (Elechiguerra et al., 2006). The characteristics of the crystals can be controlled by the thermodynamics and kinetics of the synthesis (Goia, 1998) and the great progress has been made. However, there is still need for development of chemical methods that can tailor the morphology of Pt crystals at different scales.This article describes a simple preparation and size control of small Pt-NPs stabilized by PVP with narrow size distribution by EtOH reduction method. The nanoparticles were characterized by UV-Visible optical spectroscopy, transmission electron microscopy (TEM) and powder x-ray diffractometry (XRD). Materials and methods Chemicals and materialsHydrogen hexachloroplatinate(IV) hexahydrate (H 2 PtCl 6 .6H 2 O) (Sigma-Aldrich), ethanol (C 2 H 6 O) (Merck), Poly(vinylpyrrolidone) (PVP, MW 40,000) (TCI), were of analytical grade and used as received. Double distilled water was used to prepare aqueous solutions. All of the glasswares along with teflon coated magnetic stirrer were cleaned with aqua regia for fine cleaning followed by rinsing with double distilled water. Preparation of Pt:PVP NPsAs reported earlier (Hossain et al., 2012, Teranishi et al., 1999, a mixture of ethanol/water solution (9:1, v/v, 100 mL; 90% EtOH) containing H 2 PtCl 6 (30 mM, 3.34 mL) and PVP (444 mg, PVP-monomer/Pt = 40:1) was refluxed at 90 °C in a 150 mL round bottom flask for 3 h using water bath. After cooling to room temperature, the produced Pt:PVP was purified using a dialysis membrane of cut off molecular weight 10 kDa for the removal of inorganic ions and ethanol. Finally, the purified sample was stored in an air tight desiccators after freeze drying. Larger Pt:PVP by seed mediated growthTo form larger Pt-NPs, smaller Pt:PVP NPs were used as seed particles. In a typical procedure, a mixture of total 25 mL aqueous solution of H 2 PtCl 6 (10 mM, 2.5 mL) and ethanol/water solution (9:1, v/v, 22.5 mL) were added to the 25 mL of Pt:PVP seed solution of 1.0 mM concentration. The final concentr...

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Ligand-stabilized metal clusters and colloids: properties and applications

Abstract: In this perspective some general phenomena of ligand-stabilized transition-metal clusters and colloids are introduced before some recent results on the special behaviour of such particles in catalysis are given.

Cited by 158 publications

References 15 publications

Nanohybridized Synthesis of Metal Nanoparticles and Their Organization

Nanohybridized Synthesis of Metal Nanoparticles and Their Organization

Design of Colloidal Pt Catalysts Encapsulated by Silica Nano Membranes for Enhanced Stability in H2S Streams

Tunable synthesis of platinum nanoparticles by EtOH reduction in presence of poly (vinylpyrrolidone)

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