Accounting for the very low amount of CO2 formed here and the real O2 starting concentration, an O2 conversion of only 21.6 % would theoretically satisfy the conversion observed here stoichiometrically, while in fact, the O2 conversion is complete. Therefore, it is concluded, that the remainder part of O2 has to be either engaged in the formation of surface species and/or the non-oxidative dehydrogenation as well, although O2 does not take part in the reaction according to the equation of non-oxidative dehydrogenation. This phenomenon has been described by Holz et al. as well and was experimentally studied by Simakova et al. , who found oxygen to be an intrinsic promotor in the non-oxidative dehydrogenation of ethanol. The comparison of figures 9 and 11 shows, that the carbon balance is not closed by far. For data points on the temperature ramp steady state conditions might not have been reached. However, for the plateau temperatures, this is visibly the case and concentration data points have been selected and averaged appropriately, which suggests, that a considerable amount of 2-propanol is adsorbed on the catalyst's surface in one or the other way and therefore not occurring in the carbon balance. This aspect is going to be addressed in the discussion of the DRIFTS experiments.