Synergism and kinetics of methane oxidation in the presence of a combined catalyst

Methane oxidation was studied in the presence of a combined catalyst contai ning an oxide component (Nd2O3/MgO) and a metallic component (Ni-Cr alloy, chromel-alumel thermocouple) over a wide range of parameters (temperature, pressure, and reactant ratios) and under the action of various factors on t he catalyst layer. A description of the experimentally observed phenomena ( synergism and nonstationary oscillatory kinetics) is proposed. The experime ntal data suggest that synergism is stipulated by the free-radical heteroge neous-homogeneous nature of methane oxidation. Secondary transformations of radicals into final products on the surface of the metallic component may occur in an oscillatory mode. Hydrogen and CO are formed via a common rate- limiting step. Several process features can be explained by the formation o f an oxygen buffer in the metallic component.