Catalyst temperature oscillations during partial oxidation of methane

During the partial oxidation of methane over Ni-supported catalysts, oscillations of the catalyst temperature were detected over NiO/SiO2, but not over NiO/Al2O3 and NiO/MgO. Hot spots were observed for all the three Ni-based catalysts, but only for the NiO/SiO2 catalyst were they moving down and up. This movement causes the oscillation of the catalyst temperature and is probably due to the reduction and oxidation of the catalyst by the reactants.