With i relating to carbon containing components here. In fig. , the transient molar flow rates calculated for Cα and Cβ as well as those measured for C2 and C3+ during the back-transient phase are shown for the case of a build-up duration of 7 min (see SI fig. and S4 for additional build-up durations and CH4). Based on the underlying assumptions, it can be seen that Cα is hydrogenated immediately after the switch, while Cβ is hydrogenated later on during the back-transient phase. The results for desorbing Cα and Cβ are summarized in fig. . The results in fig. . correspond to the values obtained from the transient molar flow rates during the back-transient phase. There, we assume the amount of Cα to be constant, whereas the amount of Cβ increases non-linearly to 97 µmol/gcat after 420 s TOS. After 4 h the amount of Cβ even reached 400 µmol/gcat. Again, we assume that Cβ refers to accumulation of FT intermediates on the surface.