Metal Microparticles Research Articles

Electrocatalytic Hydrogenation of Organic Compounds on a Poly[N-(5-hydroxypentyl)pyrrole] Film-Coated Electrode Incorporating Palladium Microparticles

A poly[N-(5-hydroxypentyl)pyrrole] film-coated carbon-fiber electrode incorporating palladium metal microparticles was prepared and the catalytic ability in the electrochemical hydrogenation of organic compounds was investigated. This electrode exhibited a high catalytic ability and a strong physical stability with respect to hydrogen evolution. By using this electrode, the electrocatalytic hydrogenation for organic compounds in an organic solvent–buffer solution led to an efficient formation of hydrogenated products, such as saturated compounds, amino compounds, and hydroxy compounds, in high yields and current efficiencies. Furthermore, a catalytic polymer film electrode was successfully applied to the hydrogenative deprotection of a benzyl group and the dehalogenation of bromobenzene in electroreduction media.

Electrocatalytic Hydrogenation of Acetylenes on Palladium Incorporating Poly [N-(5-Hydroxypentyl) Pyrrole] Film-Coated Electrode

Abstract The catalytic polymer film electrode which was coated with poly[N-(5-hydroxypentyl) pyrrole] film on carbon materials and incorporated palladium metal microparticles in film was prepared. By use of the electrode the electrocatalytic hydrogenation of acetylenes in organic solvent-HCl buffer solution led to the efficient formation of ethanes in high current efficiencies.

H 2O 2 from an oxidase enzyme can be detected cathodically using metal microparticles dispersed in a polymeric film electrode

H 2O 2 from an oxidase enzyme can be detected cathodically using metal microparticles dispersed in a polymeric film electrode

Sinus histiocytosis of pelvic lymph nodes after hip replacement. A histiocytic proliferation induced by cobalt-chromium and titanium.

Six men who had undergone hip replacements for degenerative joint disease or trauma subsequently had radical prostatectomies or cystoprostatectomies with bilateral pelvic lymph node dissections for adenocarcinoma of the prostate or transitional cell carcinoma of the urinary bladder. The hip prostheses implanted in three patients were known to contain cobalt-chromium alloy and titanium. The pelvic lymph nodes ipsilateral to the hip prosthesis in five patients and the bilateral pelvic nodes in the only patient with bilateral hip prosthesis had dark brown or black cut surfaces. These lymph nodes did not contain carcinoma but showed florid sinus histiocytosis characterized by large polygonal histiocytes filling and expanding sinuses and interfollicular regions. The foamy histiocytes contained cobalt-chromium and titanium microparticles by light microscopy, ultrastructure, and energy-dispersive x-ray microanalysis. The lymph nodes uninvolved by the histiocytic reaction lacked the heavy metal microparticles. Four cases were found to have a small number of polyethylene particles, which might have contributed to the histiocytic response. By immunohistochemistry, the foamy cells displayed immunoreactivity for lysozyme, alpha-1-antitrypsin, alpha-1-antichymotrypsin, and cathepsin D, providing additional support for their histiocytic derivation. To our knowledge, this is the first time that microparticles of cobalt-chromium and titanium that migrate from hip prostheses to pelvic lymph nodes have been shown to elicit a distinctive type of florid sinus histiocytosis. Pathologists should be aware of this characteristic foreign-body tissue response to avoid confusion with other types of sinus histiocytosis or with metastatic carcinoma.

Screen printed glucose electrodes based on platinised carbon particles and glucose oxidase

Simple strip type enzyme electrodes prepared from platinised Vulcan XC-72 carbon particles using silk screen printing techniques are described. Such electrodes combine the efficient electrocatalytic activity of metal microparticles with the attractive features of mass produced screen printed sensors. Immobilisation of glucose oxidase to the surface of the particles allows coupling of the biocatalytic reaction with the electrocatalytic oxidation of the liberated peroxide, thus providing a sensor for glucose with a detection limit of 2 X 10 −5 M.

Electrodeposition of platinum and palladium particles into base-hydrolyzed cellulose acetate films. Electrocatalytic/permselective surface microstructures

The behavior and advantages of new surface coatings, prepared by electrodeposition of platinum and palladium microparticles into base-hydrolyzed cellulose acetate (CA) films on glassy carbon electrodes, are described. The multifunctional character of these microstructures arises from the coupling of the permselective properties of CA with the catalytic power of dispersed metal particles. Control of the film porosity, via base hydrolysis, affects the size and distribution of the metal particles, and hence offers tailoring of the catalytic response. In particular, access to the catalytic sites (based on solute size) is manipulated via change of the hydrolysis time. Various experimental variables affecting the catalytic and transport properties are explored using different techniques. Scanning electron microscopy offers useful insights into the distribution of the metal microparticles within the CA matrix. Amperometric detection for flow injection and liquid chromatography systems is greatly improved by the multifunctional character of the metal/CA coatings.

Metal-dispersed carbon paste electrodes

The preparation of metal-dispersed carbon paste electrodes, based on mixing an organic binder with metalized graphite, is described. Such electrodes combine the efficient electrocatalytic activity of metal microparticles with the attractive properties of carbon paste matrices. The ability to catalyze the slow electrode reactions of hydrogen or organic peroxides, hydrazine compounds, ascorbic acid, and dihydronicotinamide adenine dinucleotide is illustrated

Electrocatalytic hydrogenation using precious metal microparticles in redox-active polymer films

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectrocatalytic hydrogenation using precious metal microparticles in redox-active polymer filmsLiliane Coche, Bernadette Ehui, Daniele Limosin, and Jean Claude MoutetCite this: J. Org. Chem. 1990, 55, 23, 5905–5910Publication Date (Print):November 1, 1990Publication History Published online1 May 2002Published inissue 1 November 1990https://doi.org/10.1021/jo00310a025RIGHTS & PERMISSIONSArticle Views238Altmetric-Citations38LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (753 KB) Get e-Alerts Get e-Alerts

Sedimentation of particles from a convecting fluid

THE sedimentation of particles from a convecting fluid is a process of much interest to engineers, fluid dynamicists, geologists and metallurgists. For example, the process plays a fundamental role in controlling the settling behaviour of phenocrysts in magma chambers, crystals and impurities in metallic castings and carbon microparticles in combustion chambers. Previous studies of particle settling in convecting systems1–5 have assumed that the concentration of particles is so small that their presence does not modify the convective motion. Here we present experimental results which show that convective motion due to heating from below can be affected by the presence of particles and is controlled by the bulk density of a particulate suspension, which is a function of both temperature and particle concentration. Above a certain concentration, the particle distribution initially stabilizes the bulk density gradient during sedimentation, and convection is confined to a sedimenting layer beneath a clear layer. Eventually, however, othe destabilizing thermal gradient exceeds the stabilizing effect of the particles, and a sudden overturn of the whole system results. Our experimental results agree with a simple physical model.

Preparation and characterization of SPE composites forelectrolyzers and fuel cells

Solid Polymer Electrolyte (SPE) technology is a promising technique for the development of energetically efficient electrolysers (water, brine electrolysis and organic synthesis) and power generators (H 2/O 2 fuel cell). In this paper, we present three different methods for the preparation of electrocatalyst-solid electrolyte composites: First, a procedure based on the localized precipitation of noble metal microparticles within a perflourinated ionomer membrane was developed. Then, the chemical transformation of perflourinated ionomers which lead to thermoplastic materials onto which can be pressed appropriate electrode structures was made. Finally, the preparation, characterization and use of solutions and gels of perflourinated ionomers, leading to the realization of catalyst-based structures suitable for H 2/O 2 fuel cell application, were descrived.

Electrochemical Fabrication of Amperometric Microenzyme Sensor

Enzyme electrodes were microfabricated by electrochemical incorporation of enzyme molecules into the continuously electrochemically developing micropores of platinum black particles. Two electrochemical processes, electrochemical adsorption of enzyme molecules and reductive deposition of metallic microparticles from its complexal form, were simultaneously carried out by using a microelectrode of diameter ranging from 10 to 200 μm. An amperometric glucose sensor, consisting of a glucose oxidase‐incorporated microelectrode, demonstrated high performance characteristics including high sensitivity and fast response.

ChemInform Abstract: Electrocatalytic Hydrogenation of Organic Compounds on Carbon Electrodes Modified by Precious Metal Microparticles in Redox Active Polymer Films.

ChemInformVolume 19, Issue 8 Preparative Organic Chemistry ChemInform Abstract: Electrocatalytic Hydrogenation of Organic Compounds on Carbon Electrodes Modified by Precious Metal Microparticles in Redox Active Polymer Films. L. COCHE, L. COCHE Lab. Electrochim. Org., CNRS, Univ. Sci. Technol. Med. Grenoble, 38402 Saint Martin d'Heres, Fr.Search for more papers by this authorJ.-C. MOUTET, J.-C. MOUTET Lab. Electrochim. Org., CNRS, Univ. Sci. Technol. Med. Grenoble, 38402 Saint Martin d'Heres, Fr.Search for more papers by this author L. COCHE, L. COCHE Lab. Electrochim. Org., CNRS, Univ. Sci. Technol. Med. Grenoble, 38402 Saint Martin d'Heres, Fr.Search for more papers by this authorJ.-C. MOUTET, J.-C. MOUTET Lab. Electrochim. Org., CNRS, Univ. Sci. Technol. Med. Grenoble, 38402 Saint Martin d'Heres, Fr.Search for more papers by this author First published: February 23, 1988 https://doi.org/10.1002/chin.198808081Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume19, Issue8February 23, 1988 RelatedInformation

One Step Fabrication of Microbiosensor Prepared by the Codeposition of Enzyme and Platinum Particles

Abstract Electrochemical incorporation of enzyme molecules into the growing matrix of platinum black particles is employed for the microfabrication of the enzyme electrode. Two electrochemical processes, i.e., electrochemical adsorption of enzyme molecules and electrolytic (reductive) deposition of metallic microparticles from its complex compound, are simultaneously carried out by using a microelectrode whose diameter is below 50 μm. A glucose sensor, a glucose oxidase-incorporated microelectrode, demonstrates high performance with high sensitivity and fast responsiveness.

Electrocatalytic hydrogenation of organic compounds on carbon electrodes modified by precious metal microparticles in redox active polymer films

Electrocatalytic hydrogenation of organic compounds on carbon electrodes modified by precious metal microparticles in redox active polymer films

Density-functional calculation of the fragmentation of doubly ionized spherical jelliumlike metallic microparticles.

The fragmentation of doubly charged ${X}_{N}$${}^{2+}$ (X=Na,Mg) model microparticles into two singly charged fragments ${X}_{N}$${}^{2+}$\ensuremath{\rightarrow}${X}_{P}$${}^{+}$+${X}_{N\mathrm{\ensuremath{-}}P}$${}^{+}$ has been studied as a function of N and P, by using the density-functional formalism. In contrast to naive expectations which would predict the most asymmetric channel (P=1) to be the most favorable one, we find that the main factor controlling the most favorable channel is the tendency for fragments to have a ``magic'' number of electrons: 2, 8, 18, etc. These magic numbers, which correspond to filled electronic shells in a spherically symmetric potential, are already familiar from the analysis of experiments of the relative abundance of alkaline-atom clusters produced by supersonic expansion. Our results suggest the existence of a critical number (larger than 100) for Coulomb explosion of ${\mathrm{Na}}_{\mathrm{N}}$${\mathrm{}}^{2+}$ clusters.

Aerosols of anisotropic metallic microparticles as artificial Kerr media

The use of aerosols of anisotropic metallic microparticles as composite artificial Kerr media for degenerate four wave mixing is investigated. Because of the elongated shapes and the large and negative value of the dielectric function of metal particles, nonlinear coefficients are much larger than those for insulating particles. Estimates are given of grating resolution, formation and decay times, and the attenuation of radiation owing to scattering and absorption as well as of limitations imposed by particle sedimentation.

Quantum size effects in the elastic scattering of light from small metal particles

A quantum mechanical calculation of the differential elastic scattering cross-section of light from a metal microparticle is presented. The scattering intensity is found to exhibit oscillations as a function of the frequency due to the discreteness of the electron energy levels. The magnitudes of the oscillations have a sensitive dependence on the size of the electron mean free path relative to the diameter of the particle.

Field emission of metal ions and microparticles: S P Thompson and A von Engel, J Phys D: Appl Phys, 15 (5), 1982, 925–931

Field emission of metal ions and microparticles: S P Thompson and A von Engel, J Phys D: Appl Phys, 15 (5), 1982, 925–931

Field emission of metal ions and microparticles

By applying an intense electric field to the end of a thin tungsten needle, covered with a film of molten gold, a beam of fast positive singly and multiply charged atomic and molecular Au ions and of Au microparticles is emitted from the needle tip in vacuo. When such a composite beam passes through a transverse electric field, the deflected particles form a cigar-shaped deposit on a target showing that the particles are charged and that the spot shape was distorted by a non-uniformity of the deflecting field. The absence of an undeflected deposit suggests a negligible number of uncharged beam particles. In contrast, by deflection in a transverse magnetic field B the beam is split into a number of circular spots which are found to lie on a straight line. Their displacements correspond to Aunm+ (charged microparticles). From the intensity of the individual deposits the intensity of the beam components has been estimated. The fairly sharp boundaries of the circular spots indicate that the velocity distribution of each component is relatively narrow. Thus both ions and charged microparticles seem to originate from the same apex sites and to be 'released' by conservative field forces.

Effect of the shape of the light pulse on the optical breakdown threshold of transparent dielectrics

The problem concerning the nonsteady heating by a light pulse of arbitrary shape, of an insulated metallic microparticle located in a transparent dielectric, is solved. The effect of the shape of the heating pulse on the nature of heating up of the inclusion is investigated. The results of the paper can be used for the experimental verification of the heat-conductivity theory of breakdown of solid transparent dielectrics.