title: Bamboo-shaped carbon nanotubes generated by methane thermal decomposition using Ni nanoparticles synthesized in water-oil emulsions.
abstract: Ni nanoparticles were synthesized using two water-in-oil emulsions formulated with different surfactants and using n-heptane as the organic phase and aqueous nickel acetate as the catalytic metallic precursor. Characterization by transmission electron microscopy showed that the Ni nanoparticles have diameters ranging from 3 to 12 nm, and that the surface is lightly oxidized. The decomposition of diluted methane catalyzed by the as-prepared Ni nanoparticles was studied in a thermogravimetric analyzer (TGA), operated in the 25-930°C range. The weight gains measured during the analysis showed that the Ni nanoparticles decomposed methane above 480°C, producing similar g.C/g.cat ratios (6-7) at the end of the tests. High resolution transmission electron microscopy (HRTEM) confirmed that the carbons collected at 930°C were bamboo-shaped carbon nanotubes (BSCNTs) with well defined conical compartments. The average outside diameter of the tubes was between 30 and 60 nm.
authors.affiliation: Department of Strategic Research in Refining, PDVSA-INTEVEP, Los Teques AP 76343, Caracas 1070-A, Venezuela. gonzaleziz@pdvsa.com
authors.forename: Ismael
authors.initials: I
authors.lastname: González
authors.forename: Juan
authors.initials: J
authors.lastname: De Jesus
authors.forename: Edgar
authors.initials: E
authors.lastname: Cañizales