In summary, from the analysis of the single pulse shapes we concluded that the final product CH4 is mainly formed by the reaction of H2 in the pulse with carbon containing ad-species on the catalyst, which is consistent with the very short lifetime of adsorbed hydrogen on the surface. Furthermore, the broadening of the CO2 pulses as compared to the inert Ar pulses indicates a stronger interaction of the species with the catalyst. Finally, H2O formed as a product of the methanation reaction and/or possibly by Oact removal by H2, shows a pronounced pulse broadening due to significant contributions from adsorption-desorption processes on the way through the catalyst bed, reflecting strong interactions with the catalyst surface.