resumo
The electrocatalytic activity of composite anodes, comprising metallic platinum and nanocrystalline Pt-modified Ce0.45Zr0.45La0.10O2-delta and Ce0.9Sm0.1O2-delta , was evaluated for the oxidation of dry methane in a solid oxide fuel cell (SOFC) - type reactor with yttria-stabilized zirconia solid electrolyte. At 923-1073 K, the total combustion is dominant, whilst above 1100 K the composite anodes exhibit significant catalytic activity towards the partial oxidation of methane (POM). At 1223 K and for a O-2:CH4 ratio equal to 0.5, stoichiometric for the POM reaction, CO selectivity and CH4 conversion over Ce0.9Sm0.1O2-delta /Pt achieves 55% and 41%, respectively. Under these conditions, Ce0.45Zr0.45La0.10O2-delta /Pt anodes possess higher catalytic activity for partial oxidation, associated with the lower lattice oxygen mobility and instability of the Ce0.45Zr0.45La0.10O2-delta cubic fluorite structure, and provide 54% conversion efficiency with 73% selectivity to carbon monoxide. Further increase in CH4 conversion and CO selectivity can be achieved by packing the reactor with an additional catalyst, such as Pt-promoted Ce0.45Zr0.45La0.10O2-delta or LaNiO3-delta / Al2O3 .
palavras-chave
OXIDE FUEL-CELLS; DOPED CERIA; OXYGEN MOBILITY; LATTICE OXYGEN; SYNTHESIS GAS; MIXED OXIDES; SOFC ANODES; SYNGAS; CATALYSTS; NI
categoria
Chemistry
autores
Yaremchenko, AA; Kharton, VV; Valente, AA; Frolova, EV; Ivanovskaya, MI; Kovalevsky, AV; Marques, FMB; Rocha, J
nossos autores
Aleksey Yaremchenko
Investigador Principal
Anabela Tavares Aguiar Valente
Investigador Principal
Andrei Kavaleuski
Investigador principal
Fernando Manuel Bico Marques
Professor Catedrático
João Rocha
Prof. Catedrático