Discovery of a palladium-platinum-gold-mercury bitumen in the Boss mine, Clark County, Nevada

A bitumen containing high concentrations of sulfur, palladium, platinum, gold, and mercury has been found in the Boss mine, Clark County, Nevada, where rich ores of 'invisible' palladium and platinum were mined from 1916 to 1919. The bitumen, analyzed with X-ray energy dispersive spectrometry on areas devoid of discrete particles down to a 40 Å limit, contains 2.74 wt percent Pd + Pt + Au (Pd = 1.85%) and 5.83 wt percent Hg. It is associated with particulate potarite (Pd, Au, Pt) Hg, native gold, plumbojarosite, hydronium jarosite, argentojarosite, florencite, and bismuth oxides. The first four mineral species are also found included in the bitumen. The paragenesis was derivation and formation of bitumen from the local limestone, followed by interaction with the hydrothermal potarite and the supergene jarosite. This type of organic material, highly enriched in platinum group elements, previously had been reported only in Polish Kupferschiefer thucholite.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

TiO2-supported Rh nanoparticles: From green catalyst preparation to application in arene hydrogenation in neat water

45-4 FIELD Section Title:Industrial Organic Chemicals, Leather, Fats, and Waxes 67 Ecole Nationale Superieure de Chimie de Rennes, UMR 6226, CNRS, Rennes, Fr. FIELD URL: written in EnglishInternational audienceTiO2-supported Rh(0) nanoparticles were prepd. by an easy method under mild conditions in neat water. They proved to be highly active catalysts for arene hydrogenation in water with TOFs up to 33 333 h-1. [on SciFinder(R)

Loop-stabilized BAB triblock copolymer morphologies by PISA in water

International audienceA straightforward strategy to synthesize in water, loop-stabilized particles via PISA is developed. These particular structures can in theory be obtained through the synthesis of amphiphilic BAB triblock copolymers, starting from a hydrophilic middle block A, which is chain extended in an aqueous PISA process by two hydrophobic external blocks B. For that purpose, symmetrical bifunctional poly(N,N-dimethylacrylamide) macroRAFT agents with a central benzoic acid group and an alkyl chain as Z group are used in the aqueous dispersion polymerization of diacetone acrylamide. For the first time, stable BAB flower-like particles are formed via PISA in pure water. It is shown that the colloidal stability and the resulting particle morphology (spheres, worms, vesicles) strongly depend on the degree of ionization of the central charge in the stabilizer loop, thus on the pH at which PISA is performed. Moreover, the influence of the length of the alkyl Z group (dodecyl and butyl alkyl chains) on the colloidal stability is studied

From mesoporous alumina to Pt/Al2O3 catalyst: A comparative study of the aluminas synthesis in aqueous medium, physicochemical properties and stability

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Co, Fe and CoFe oxide nanoparticle assemblies within an ordered silica matrix: effects of the metal ions and synthesis pathway on the microstructure and magnetic properties

The magnetic properties of nanoparticle assemblies strongly depend on the structural and morphological characteristics of the individual nanoparticles as well as on their organization within the assembly. Here, we present the synthesis of cobalt and/or iron oxide nanoparticles within the ordered mesoporosity of a silica monolith by two different synthesis pathways (using either Prussian blue analogues or nitrate salts as a precursor). We describe the influence of the nature of the metal ion and of the synthesis pathway on the morphology of the nanoparticles. With respect to these observations, we present and discuss the temperature-dependent magnetic behaviors of the final nanocomposites

Facile synthesis of palladium nanowires by a soft templating method

International audienceVery long and thin monocrystalline Pd nanowires were synthesized by decomposition using hydrazine vapour treatment of Pd2(DBA)3 confined in the oil phase of a hexagonal mesophase. The mesophase is composed of toluene-swollen tubes, doped with the Pd precursor, stabilized by a monolayer of surfactant and cosurfactant molecules, and arranged on a triangular lattice in water. Our synthesis is selective and the experiments show that both the confinement and the nature of the surfactant are essential to obtain these Pd nanowires

Polyol Process Coupled to Cold Plasma as a New and Efficient Nanohydride Processing Method: Nano-Ni 2 H as a Case Study

International audienceAn alternative route for metal hydrogenation has been investigated: cold plasma hydrogen implantation on polyol-made transition metal nanoparticles. This treatment applied to a challenging system, Ni-H, induces a reordering of the metal lattice, and superstructure lines have been observed by both Bragg-Brentano and grazing incidence X-ray diffraction. The resulting intermetallic structure is similar to those obtained by very high-pressure hydrogenation of nickel and prompt us to suggest that plasma-based hydrogen implantation in nanometals is likely to generate unusual metal hydride, opening new opportunities in chemisorption hydrogen storage. Typically, almost isotropic in shape and about 30 nm sized hexagonal-packed Ni 2 H single crystals were produced starting from similarly sized cubic face-centred Ni polycrystals