DEACTIVATION OF SUPPORTED NICKEL-CATALYSTS DURING THE REFORMING OF METHANE BY CARBON-DIOXIDE

Several supported nickel catalysts were tested for the methane reforming reaction at 700 degrees C. The initial activity is found to depend essentially on the state of the nickel phase (reduction and dispersion) and little on its environment (support, additive). The product distribution is controlled by the WGS equilibrium. The zero order aging process is mostly due to carbon deposition, though slight Ni sintering also occurs. Among the deposited carbon, only a stable form, possibly arising from the CO disproportionation, would poison the Ni particles. Another form, less stable and arising from methane activation, is rapidly accumulated on the catalyst, but at a low level and limited extent.