VILMARIA APARECIDA RIBEIRO
2 resultados
Resultados de Busca
Agora exibindo 1 - 2 de 2
Artigo IPEN-doc 24380 Palladium nanoparticles supported on phosphorus-doped carbon for ethanol electro-oxidation in alkaline media2018 - SILVA, JULIO C.M.; FREITAS, ISABEL C. de; NETO, ALMIR O.; SPINACE, ESTEVAM V.; RIBEIRO, VILMARIA A.Palladium nanoparticles supported on carbonVulcan XC72 (Pd/C) and on phosphorus-doped carbon (Pd/P-C) were prepared by an alcohol reduction process. X-ray diffractograms of Pd/C and Pd/P-C showed the typical face-centered cubic (fcc) structure of Pd. The crystallite sizes of Pd fcc phase were around 8 nm for both samples. X-ray photoelectron spectroscopy revealed to Pd/C and Pd/P-C that Pd was found predominantly in the metallic state and to Pd/P-C, the presence of P increases the amount of oxygen on the electrocatalyst surface. The activity and stability of the electrocatalyts for ethanol electro-oxidation in alkalinemedium was investigated by cyclic voltammetry and chronoamperometry experiments. The peak current density on Pd/P-C was 50% higher than on Pd/C, while the current density measured after 30 min at − 0.35 V vs. Hg/ HgO was 65% higher on Pd/P-C than on Pd/C. The enhancement of the catalytic activity of Pd/P-C electrocatalyst might be related to the presence of higher amounts of oxygen species on the surface, which could contribute to the oxidation of intermediates formed during ethanol electro-oxidation process.Artigo IPEN-doc 17739 Pt/Ru/carbon hybrid materials prepared by hydrothermal carbonization as electrocatalysts for methanol electrooxidation2012 - TUSI, M.M.; POLANCO, N.S.O.; BRANDALISE, M.; CORREA, O.V.; SILVA, A.C.; RIBEIRO, V.A.; NETO, ALMIR O.; SPINACE, E.V.