Navegando por Assunto "Metanol"

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Acesso aberto (Open Access)
Desenvolvimento de conjunto membrana-eletrodos para célula a combustível de metanol direto passiva
(2010) FERREIRA, Eli Carlos Lisboa; QUADROS, Fabrício Monteiro; SOUZA, José Pio Iúdice de; TANAKA, Auro Atsushi
Direct methanol fuel cells (DMFCs) without external pumps or other ancillary devices for fuel and oxidant supply are known as passive DMFCs and are potential candidates to replace lithium-ion batteries in powering portable electronic devices. This paper presents the results obtained from a membrane electrode assembly (MEA) specifically designed for passive DMFCs. Appropriated electrocatalysts were prepared and the effect of their loadings was investigated. Two types of gas diffusion layers (GDL) were also tested. The influence of the methanol concentration was analyzed in each case. The best MEA performance presented a maximum power density of 11.94 mW cm-2.
Acesso aberto (Open Access)
Estudo de eletrocatalisadores de PtRu, PtRuRh e PtRuPd obtidos por modificação no Método Borohidreto de Sódio para eletro-oxidação de metanol e etanol
(Universidade Federal do Pará, 2016-01-25) ANDRADE, Flávio Vargas; SOUZA, José Pio Iúdice de; http://lattes.cnpq.br/1448978342555218
PtRu, PtRuRh and PtRuPd electrocatalysts supported on carbon has been widely studied for electro-oxidation of methanol and ethanol. Among different possibilities of preparing these electrocatalysts is the method of reducing with sodium borohydride. For the catalytic activity is optimized, it is necessary that the electrocatalyst is distributed evenly. One possibility is the use of complex precursor salts, including those with amine linker. In this work, we tried to assess the effect of adding an ammonium hydroxide solution (NH4OH) the solution of precursors. The electrocatalysts were characterized physically by Transmission Electron Microscopy (TEM), Energy Dispersive X-ray (EDX) and X-ray diffraction (XRD). For the electrochemical characterization, the techniques of chronoamperometry and cyclic voltammetry were used. The results of EDX showed that the compositions of the electrocatalysts were very close to the nominal composition. The crystallite size and the lattice parameter obtained by XRD showed changes with the change of the method. The TEM results show a homogeneous distribution more particle on electrocatalysts preparations with the addition of NH4OH solution 4 mol L-1 although this is not be determinant in electrocatalytic activity. Nos electrochemical testicles, as chains were for standard electro-oxidation of CO and load monolayer for the mass activity and compared this way. The cyclic voltammetry and chronoamperometry results showed different activities paragraph an electro-oxidation of methanol and ethanol. The results of DEMS electrocatalysts trimetallic of PtRuRh and PtRuPd showed different amounts of products and volatile. This way possible and establish an activity order these electrocatalysts.