Methane dry reforming over well-dispersed Ni catalyst prepared from perovskite-type mixed oxides

Abstract

Methane dry reforming with carbon dioxide was performed using perovskite-type mixed oxide catalysts, La 1-x Sr x NiO 3 (x = 0, 0.1) and La 2-x Sr x NiO 4 (x = 0-1) at 600-900°C and atmospheric pressure. Catalytic activity and resistance against coke formation were varied with the type of perovskite and the amount of Sr-substitution. LaNiO 3 showed high activity without coke formation while La 2 NiO 4 did not show any activity. Among Sr-substituted catalysts, La 0.9 Sr 0.1 NiO 3 and La 1.8 Sr 0.2 NiO 4 had the highest catalytic activity without coke formation. For these catalysts, initially the catalytic activity increased with time and then reached a steady state. The XRD spectra of used catalysts showed that catalysts were transformed to mixed phases of La 2 O 2 CO 3 and SrCO 3 with highly dispersed Ni metal during the reaction. This transformation could be caused by the removal of lattice oxygen by Sr-substitution, which was promoted by the reducing atmosphere of the reaction (CH 4 /CO 2 = 1). The enhanced catalytic activity of Sr-substituted perovskite could come from dual active sites, La 2 O 3 for CO 2 adsorption and Ni for CH 4 activation.