After a suitable operating point was identified, the dynamic behavior of the CO-hydrogenation was investigated using the experimental setup and methodology described in detail by Meyer et al. and Gäßler et al. , using the PTK method. The PTK method involves periodic step changes between two feed gas compositions and analysis of the gas composition at the reactor outlet via MS with a high temporal resolution of 0.5 s. The compositions in the feed gas lines were adjusted via MFCs (Bronkhorst EL-Flow Prestige) and can provide H2, He, Ar, and CO. The switching was executed via a pressure actuated highspeed valve (FITOK Boss) and was assumed to be an ideal step, as the switching process was faster than the temporal resolution of the MS. The gas feed line was switched between a H2/He (back-transient phase) and a CO/Ar/H2/He mixture (build-up phase) with constant volumetric flow rate. During the build-up phase, the reactants flow into the catalyst bed, adsorb on the catalyst and the reaction starts, while in the back-transient phase, remaining intermediates are hydrogenated to products and can desorb. Ar acts as an internal standard, representing the RTD for each up-and downward switching event. At the reactor outlet, additionally H2 and Ne was added. H2 acts as a dilution to minimize the residence time in the tubing after the reactor and to ensure more consistent ionisation in the MS measurement. Due to the known molar flow rate of the external standard Ne, the total molar flow rate can be derived from the measured molar fractions from the MS.