Synergetic effect of a mixture of activated carbon + Ni/Al2O3 used as catalysts for the CO2 reforming of CH4 Original Research Article

In this work the catalytic activity of heterogeneous mixtures of an activated carbon, FY5, and an in-lab prepared Ni/Al2O3 in the CO2 reforming of CH4 reaction was investigated. Initially, the reaction was carried out over FY5 and Ni/Al2O3 separately. Under the operating conditions employed, the CO2 and CH4 conversions obtained over FY5 were negligible, whereas they were high and steady over Ni/Al2O3. In the latter case, it was found that the spinel NiAl2O4 was formed due to the interaction between the reduced Ni and the support during heating under a N2 atmosphere. The reaction was also carried out over different mixtures of FY5 + Ni/Al2O3. The experimental conversions thus attained were higher than the conversions calculated by adding the weighted individual conversions (mixtures law). Therefore, a synergetic effect exists between the carbonaceous fraction and the metal-based fraction. This effect was found to increase with temperature. Differences between the experimental and theoretical CO2 conversion were also observed to increase when the proportion of FY5 in the mixture was increased, whereas in the case of CH4 conversion, the increase depended on the proportion of Ni/Al2O3 added. It was also observed that, when a heterogeneous mixture FY5 + Ni/Al2O3 was used as catalyst for the CO2 reforming of methane, the decomposition of CH4 occurred preferentially over the Ni-based fraction and that CO2 tended to gasify both the initial carbonaceous fraction and the carbon deposits from methane.