The study of the partial oxidation of methane over nickel foils has been carried out over a wide range of reactor temperatures (748-930degreesC) and feed-gas compositions(Ar/CH4/O-2), ranging form 30:29:1 to 30:12:18 cm(3) min(-1) at atmospheric pressure. The product formation shows pronounced oscillations. A modified thermocouple was designed to measure the temperature while the interposed nickel foil worked as a catalyst. The oscillations have been attributed to the cyclic reduction and oxidation of the nickel surface in the specific reaction environment at elevated temperatures.