Dry reforming of methane over LaNi1-yByO3 +/-delta(B=Mg, Co) perovskites used as catalyst precursor

Perovskites LaNiO3, LaNi1-xMgxO3-delta and LaNi1-xCoxO3-delta were synthesized by auto combustion method. TPR analysis reveled that Mg or Co substituted perovskites were more difficult to reduce. The perovskites were evaluated as catalyst precursors in the dry reforming of methane. Catalysts obtained by reduction of LaNiO3 and LaNi1-xMgxO3-delta perovskite had the highest catalytic activity for CO2 reforming of CH4 at 700 degrees C using drastic reaction conditions (10 mg of catalyst, a mixture of CH4/CO2 without dilution gas). Methane and carbon dioxide conversions were 57% and 67%, respectively, with a H-2/CO ratio equal to 0.47. The presence of cobalt leads to a decrease of the catalytic activity. This decreasing of activity may be attributed to the Co-Ni alloy formation. Computational calculations revealed that Ni atom cleaves the C-H atom while Co is not able to activate the CH4 molecule. The interaction energy of CH4 with the Ni and CO atom was 18 kcal/mol and 0.7 kcal/mol, respectively. The catalysts were characterized by TPR, TEM and in situ XRD. (c) 2007 Elsevier B.V. All rights reserved.