0000000000646233

AUTHOR

La Parola

showing 3 related works from this author

Synergetic effect of gold in Au/Pd catalysts during hydrodesulfurization reactions of model compounds

2003

Abstract The simultaneous formation of colloidal dispersions of Pd and Au metal particles protected by the organic polymer polyvinylpyrrolidone (PVP) in reducing alcohol solution was used for the synthesis of new silica-supported monometallic and bimetallic Au x Pd y catalysts with different x / y ratios. The samples, with a 2 wt% total metal loading, after air calcinations at 673 K to remove the PVP, were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and FTIR spectra of chemisorbed CO. Formation of alloyed Au x Pd y particles of different metal composition with consequent modification of their electronic and geometric properties was ascertained. The catalytic activi…

Inorganic chemistrychemistry.chemical_elementCatalysisCatalysisMetalchemistry.chemical_compoundAu-Pd catalysts; Polyvinylpyrrolidone; Hydrodesulfurization; HDS; Thiophene; DibenzothiophenechemistryTransition metalDibenzothiophenevisual_artThiophenevisual_art.visual_art_mediumPhysical and Theoretical ChemistryBimetallic stripHydrodesulfurizationPalladiumJournal of Catalysis
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Chemical modification of carbon nanomaterials (SWCNTs, DWCNTs, MWCNTs and SWCNHs) with diphenyl dichalcogenides

2015

Control over chemical functionalization is a crucial point in the field of nanotechnology. Herein, we present the covalent functionalization of several carbon nanoforms (single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes and carbon nanohorns) by means of diphenyl dichalcogenides. These ones show different reactivity to the nanomaterials and are able to modify their electronic properties depending on the electronegativity of the functionalizing heteroatom. Theoretical calculations were also performed to support the experimental results. All the modified structured nanocarbons were thoroughly characterized by TGA Raman, XPS, UV/Vis/nIR, IR and TEM te…

Chemical substanceMaterials scienceHeteroatomCarbon nanohornSelective chemistry of single-walled nanotubeschemistry.chemical_elementNanotechnologyCarbon nanotubeCarbon nanotubelaw.inventionNanomaterialschalcogenidesymbols.namesakeSWCNTlawGeneral Materials ScienceReactivity (chemistry)Raman spectroscopy XPS spectroscopyCarbon nanomaterials; chemical modificationSettore CHIM/06 - Chimica OrganicaCarbon nanomaterialchemistrysymbolsfunctionalizationCarbon nanomaterialsChemical functionalizationRaman spectroscopychemical modificationCarbon
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Long term X-ray spectral variability of the nucleus of M81

2003

We have analysed the soft X-ray emission from the nuclear source of the nearby spiral galaxy M81, using the available data collected with ROSAT, ASCA, BeppoSAX and Chandra. The source flux is highly variable, showing (sometimes dramatic: a factor of 4 in 20 days) variability at different timescales, from 2 days to 4 years, and in particular a steady increase of the flux by a factor of >~ 2 over 4 years, broken by rapid flares. After accounting for the extended component resolved by Chandra, the nuclear soft X-ray spectrum (from ROSAT/PSPC, BeppoSAX/LECS and Chandra data) cannot be fitted well with a single absorbed power-law model. Acceptable fits are obtained adding an extra component, …

PhysicsSolar massSpiral galaxyAstrophysics::High Energy Astrophysical PhenomenaAstrophysics (astro-ph)FluxFOS: Physical sciencesAstronomy and AstrophysicsAstrophysicsRadiusAstrophysics::Cosmology and Extragalactic AstrophysicsAstrophysicsBlack holeRotating black holeSpace and Planetary ScienceROSATX-ray x rays sources ULXsAbsorption (electromagnetic radiation)Astrophysics::Galaxy Astrophysics
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