La-Sr-Ni-Co-O based perovskite-type solid solutions as catalyst precursors in the CO2 reforming of methane

Abstract

La1−xSrxNi0.4Co0.6O3 and La0.8Sr0.2Ni1−yCoyO3 solid solutions with perovskite-type structure were syn- thesized by the sol–gel resin method and used as catalytic precursors in the dry reforming of methane withCO2 tosyngas,between873and1073Katatmosphericpressureundercontinuousflowofreactant gaseswithCH4/CO2 =1ratio.ThesequaternaryoxideswerecharacterizedbyX-raydiffraction(XRD),BET specific surface area and temperature-programmed reduction (TPR) techniques. XRD analyses of the more intense diffraction peaks and cell parameter measurements showed forma- tionofLa-Sr-Ni-Co-OsolidsolutionswithLa0.9Sr0.1CoO3 and/orLa0.9Sr0.1NiO3 asthemaincrystallographic phasespresentonthesolidsdependingonthedegreeofsubstitution.TPRanalysesshowedthatSrdoping decreases the temperature of reduction via formation of intermediary species producing Ni0, Co 0 with particle sizes in the range of nanometers over the SrO and La2O3 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.