Modifying perovskite-type oxide catalyst LaNiO₃ with Ce for carbon dioxide reforming of methane

Perovskite-type oxide catalysts LaNiO₃ and La _1-xCe_xNiO₃ (x ≤ 0.5) were prepared by the Pechini method and used as catalysts for carbon dioxide reforming of methane to form synthesis gas (H₂ + CO). The gaseous reactants consisted of CO₂ and CH₄ in a molar ratio of 1:1. At a GHSV of 10,000 hr^-1, CH₄ conversion over LaNiO₃ catalyst increased from 66% at 600 C to 94% at 800 C, while CO₂ conversion increased from 51% to 92%. The achieved selectivities of CO and H₂ were 33% and 57%, respectively, at 600 C. To prevent the deposition of carbon and the sintering nickel species, some of the Ni in perovskite-type oxide catalyst was substituted by Ce. Ce provided lattice oxygen vacancies, which activated C-H bonds, and increased the selectivity of H₂ to 61% at 600 C. XRD analysis indicates that the catalyst exhibited a typical perovskite spinel structure and formed La₂O₂CO₃ phases after CO₂ reforming. The FE-SEM results reveal carbon whisker of the LaNiO₃ catalyst and the BET analysis indicates that the specific surface area increases after the reforming reaction. The H₂-TPR results confirm that Ce metals can store and provide oxygen.