The application of the PTK method is promising, since it is a dynamic method (see Figure ), where different operation modes of the catalyst are periodically switched on and off. The period consists of two phases, the build-up phase and the back-transient phase. During the build-up phase, all reactants of the system are dosed together, while in the back-transient phase the composition of the feed is changed and another state is approached, in this study being a state without reaction. The PTK method also allows to extract information on the current catalyst activity in each period, enabling a direct comparison of data with results from steady-state experiments. The time-frame for comparison can be extracted from the build-up phase of the PTK method, the so-called pseudo-steady-state. Furthermore, it is possible to distinguish between TOT (time on temperature) and TOS (time on stream), which can be used to separate thermal deactivation from chemical deactivation (see Figure ). The differentiation into the two characteristic times helps to identify what Pérez-Ramírez et al. call the deactivation modes . Beside these main features, it is possible to distinguish reversible from irreversible deactivation processes, if one of the half-periods in the PTK is able to recover the activity of the preceding half-period. In this case, the observed deactivation during PTK is less than expected from the steady-state operation with identical TOS. Therefore, the PTK-method is a suitable investigation method to identify possible deactivation mechanisms and thus reduce the high experimental effort associated with conventional techniques (see ). We would like to emphasise that the versatility of the method goes beyond this, as the parameter field of the dynamic operation is large. As shown above, the parameters for the dynamic operation includes period duration, the time ratio of build-up and back-transient as well as the composition of the feed. However, we will stick to a very simple approach in this explorative study.