The microkinetics of the oxidation of methane on Ru/Al2O3 is developed using a TAP reactor. The shapes of the response curves of reactants and products are used to identify the elementary reactions and their rate parameters. The support, which strongly adsorbs H2O, participates in the reaction sequence through its supply of hydroxyl to metal particles by spillover, and this step is of kinetic significance. The relative rates of the elementary reactions that give overall partial oxidation or total oxidation are discussed. (C) 2003 Elsevier Science Ltd. All rights reserved.