La-Sr-Ni-Co-O based perovskite-type solid solutions as catalyst precursors in the CO sub(2) reforming of methane

• Published in: Journal of power sources 2010-04, Vol.195 (7), p.1765-1771
• Main Authors: Valderrama, Gustavo, Kiennemann, Alain, Goldwasser, Mireya R
• Format: Article
• Language: English
• ISSN: 0378-7753
• DOI: 10.1016/j.jpowsour.2009.10.004

La sub(1-x)Sr sub(x)Ni sub(0.4)Co sub(0.6)O sub(3) and La sub(0.8)Sr sub(0.2)Ni sub(1-y)Co sub(y)O sub(3) solid solutions with perovskite-type structure were synthesized by the sol-gel resin method and used as catalytic precursors in the dry reforming of methane with CO sub(2) to syngas, between 873 and 1073 K at atmospheric pressure under continuous flow of reactant gases with CH sub(4)/CO sub(2) = 1 ratio. These quaternary oxides were characterized by X-ray diffraction (XRD), BET specific surface area and temperature-programmed reduction (TPR) techniques. XRD analyses of the more intense diffraction peaks and cell parameter measurements showed formation of La-Sr-Ni-Co-O solid solutions with La sub(0.9)Sr sub(0.1)CoO sub(3) and/or La sub(0.9)Sr sub(0.1)NiO sub(3) as the main crystallographic phases present on the solids depending on the degree of substitution. TPR analyses showed that Sr doping decreases the temperature of reduction via formation of intermediary species producing Ni super(0), Co super(0) with particle sizes in the range of nanometers over the SrO and La sub(2)O sub(3) phases. These metallic nano particles highly dispersed in the solid matrix are responsible for the high activity shown during the reaction and avoid carbon formation. The presence of Sr in doping quantities also promotes the secondary reactions of carbon formation and water-gas shift in a very small extension during the dry reforming reaction.