The accumulated formation and consumption of the different CO2 isotopologues (Figure ) differed mainly by the number of exchanged oxygen species at the end of the pulse sequence from the previous experiments. It is now around 2.010 21 O atoms gcat -1 , i.e., in between the previous values. Furthermore, the exchange probability (red dots in Figure ) decayed only to about 0.35, i.e., the decay is significantly less than in the previous two measurements.