Complex dynamic phenomena-oscillations and temperature waves-are observed during partial oxidation of methane to synthesis gas over Ni-containing metal catalysts (Ni metal foam and chromel-alumel thermocouple). Kinetic analysis of oscillatory process shows that a substantial amount of oxygen and carbon is stored and evolved by catalysts during the cycle. A sharp splash of activity is observed when amounts of stored oxygen and carbon are minimal. It was concluded that the oscillatory behaviour could be due to a difference in the activities of C- and O-covered and clean metal. A "direct" mechanism of CO and H-2 formation without intermediate total oxidation is more probable than a "sequential" one. (C) 2004 Elsevier B.V. All rights reserved.