Preparation of Colloidal Transition Metals in Polymers by Reduction with Alcohols or Ethers

Hirai, Hidefumi; Nakao, Yukimichi; Toshima, Naoki

doi:10.1080/00222337908056685

Cited by 347 publications

(183 citation statements)

References 11 publications

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“…There have been many papers describing gold nanoparticle generation and stabilization, even with gold cores containing only 11, 34, 55 gold atoms (23); but as our interest lay in the catalytic properties of gold metal, we focused our attention on preparing gold particles in a diameter range of 1-10 nm where the metallic character should be preserved and the specific catalytic properties of gold should be observed (15). Thus, as a preliminary approach, we focused our attention on the classical generation of protected sols involving the reduction of Au(III) salts in the presence of the macromolecules poly(vinyl pyrrolidone) (PVP) (24) or poly(vinyl alcohol) (PVA) (25).…”

Section: Supported Gold Solsmentioning

confidence: 99%

New gold catalysts for liquid phase oxidation

1999

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A pre-requisite for good catalytic activity with supported gold is that the metal is present as nanoparticles, but no suitable method for depositing gold on carbon as nanoparticles has previously been reported. The deposition precipitation method which has been used successfully for catalyst preparation with other supports, produces large aggregates with carbon. It is now shown, however, that pre-reduced gold sol is a satisfactory method for preparing gold on carbon catalysts as long as an appropriate choice of sol is made. In this paper the activity of gold on carbon catalysts prepared in a number of different ways is compared in a standardized liquid phase organic oxidation reaction. The activity for Aule catalysts prepared by the sol method can show a two-fold increase compared with a similar catalyst prepared by deposition precipitation.

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Section: Supported Gold Solsmentioning

confidence: 99%

New gold catalysts for liquid phase oxidation

1999

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“…(first a reduction from AuCl 3 to AuCl around 160°Cand then a second reduction to metallic gold at ∼200°C) and oxidation of the organic compounds that can act as reducing agents, donating electrons to gold ions and thereby leading to Au NP nucleation. 60,61 Cross-sectional TEM images ( Figure 5) show Au NPs homogeneously dispersed through the film thickness, but other crystalline phases can be seen in the 600°C annealed sample. Fast Fourier transform (FFT) analysis of highresolution TEM images ( Figure 6) has been performed to measure lattice distances, and a comparison with theoretical data for different phases has been made.…”

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confidence: 99%

Au Nanoparticles in Nanocrystalline TiO₂−NiO Films for SPR-Based, Selective H₂S Gas Sensing

et al. 2010

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Thin films composed of Au nanoparticles dispersed inside a TiO 2 -NiO mixed oxide matrix are prepared by the sol-gel method, resulting in nanostructured composites with a morphology and crystallinity that depend on synthesis parameters and thermal treatment. Their functional activity as hydrogen sulfide optical sensors is due to Au-localized surface plasmon resonance (SPR) which is reversible. The detection sensitivity is shown to be down to a few parts per million of H 2 S, and almost no interference in response is observed during simultaneous exposure to CO or H 2 , resulting in a highly sensitive and selective sensor for hydrogen sulfide detection. For mechanistic studies, experimental evidence using reaction product analysis and thin film surface characterization suggests a direct catalytic oxidation of H 2 S over the Au-TiO 2 -NiO nanocomposite film.

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“…Colloidal dispersions of poly(N-vinyl-2-pyrrolidone)-protected Pt, Pd, Rh, and Au nanoparticles were prepared using an alcohol reduction method (Hirai et al, 1979). 50 mL of water/ethanol (1/1, v/v) solution containing 1 mM metal salts and 40 mM poly(N-vinyl-2-pyrrolidone) (monomer unit) was refluxed for 2 h, resulting in the formation of typical colored sols of metal nanoparticles.…”

Section: Preparation Of Metal Nanoparticles For Reactive Oxygen Scavementioning

confidence: 99%

“…Furthermore, Ag is inexpensive metal compared with Au. The colloidal dispersions of Ag and Rh monometallic nanoparticles protected by poly(N-vinyl-2-pyrrolidone) (PVP), a water soluble polymer, were prepared by an alcohol reduction method (Hirai et al, 1979). Average diameters of Ag and Rh monometallic nanoparticles were 7.5 nm and 2.2 nm, respectively.…”

Section: Siver-core/rhodium-shell Bimetallic Nanoparticlesmentioning

confidence: 99%

Self-Organization of Silver-Core Bimetallic Nanoparticles and Their Application for Catalytic Reaction

Hirakawa¹

2012

Smart Nanoparticles Technology

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Preparation of Colloidal Transition Metals in Polymers by Reduction with Alcohols or Ethers

Cited by 347 publications

References 11 publications

New gold catalysts for liquid phase oxidation

New gold catalysts for liquid phase oxidation

Au Nanoparticles in Nanocrystalline TiO₂−NiO Films for SPR-Based, Selective H₂S Gas Sensing

Self-Organization of Silver-Core Bimetallic Nanoparticles and Their Application for Catalytic Reaction

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Preparation of Colloidal Transition Metals in Polymers by Reduction with Alcohols or Ethers

Cited by 347 publications

References 11 publications

New gold catalysts for liquid phase oxidation

New gold catalysts for liquid phase oxidation

Au Nanoparticles in Nanocrystalline TiO2−NiO Films for SPR-Based, Selective H2S Gas Sensing

Self-Organization of Silver-Core Bimetallic Nanoparticles and Their Application for Catalytic Reaction

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Product

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Au Nanoparticles in Nanocrystalline TiO₂−NiO Films for SPR-Based, Selective H₂S Gas Sensing