In the continuous-flow reactor studies, a gap in the carbon balance was observed. As shown by figure , a considerable amount of surface species is detected at 400 °C. Their signals even increase in intensity and broadness after 15 and 30 minutes at 400 °C, which can be interpreted as an accumulation of surface species not observable in the carbon balance. Table displays the percentual gaps in the carbon balance, taking into account the formation of acetone and CO2. The gaps in the lower crystallinity sample are higher than in the higher crystallinity sample and higher at higher oxygen levels. In the continuous-flow reactor studies, the low crystallinity sample was found to be more selective towards total combustion and partial oxidation processes generally and compared to the higher crystallinity sample, specifically. CO2-TPD experiments revealed CO2 desorption maxima at 541 °C and 558 °C, respectively, setting on above 400 °C. Putting these pieces of information together, it is assumed, that the gaps in carbon balance are due to large amounts of carbonate or acetate adsorbates formed and accumulated at the relatively high molar reagent flows at temperatures not sufficiently high to spark desorption as or combustion to CO2. Table shows the phase composition of the samples after the experiments according to ex-situ XRD. While no metal formation was found after the continuous flow reactor experiments at a 2-propanol:O2 ratio of 2:1, some was found in the operando experiments. In contrast, an agreement regarding the abundance of NiO is found for that ratio. For the 2-propanol:O2 ratio of 1:1, metal formation was found in the continuous flow reactor experiments, but not in the operando experiments. However, it is noted, that both the absolute concentration values and the number of cycles carried out differ in the experiments. In the large crystallite size samples, the phase compositions after both types of experiment did not change.