Catalytic Reforming of Methane Over Ni–La₂O₃ and Ni–CeO₂ Catalysts Prepared by Sol-Gel Method

Abstract

Lantanium and Cerium supported Nickel catalysts with Ni-loading close to 15 %wt were synthesized using sol-gel methods in order to design efficient catalysts for the dry reforming of methane to produce syngas (H₂ + CO). The catalytic test was performed after calcining the as-prepared samples at 700 °C and subsequent in situ reduction was performed under hydrogen flow at 600 °C. The resulting catalysts were characterized by X-ray diffraction (XRD), Temperature Programmed Reduction (TPR), transmission electron microscopy (TEM) and N₂ adsorption-desorption isotherm measurements. The investigation of the catalytic performances of Ni–CeO₂ and Ni–La₂O₃ catalysts prepared by sol gel method (SG), for a duration of 12 h, under a reaction CH₄/CO₂ shows that, for the same synthesis method, the efficiency varies with according to the support nature. Indeed, conversions and yields are higher in the presence of the lanthanum than with the cerium support (XCO₂ = 18% and YCo = 15% for Ni–La compared of XCO₂ = 8% and YCo = 6% for Ni–Ce. Comparing the catalysts stability, we can notice that it is 100% (no deactivation) in the presence of Ni–La₂O₃ catalyst compared to Ni–CeO₂, which showed a high deactivation (78% after 12 h of reaction). This difference in stability is probably related to the perovskite structure and to the strong interactions between the active phase and the support, reinforced by the basicity of lanthanum support which inhibits carbon deposition during the CH₄/CO₂ reaction.