The specific binding of CO2 is explained by the presence of pyrrolic N species (Figure ). For a correlation to the chemical bonding within the optimized sensor, surface X-ray photoelectron spectroscopy (XPS), global IR spectroscopy and EELS bond analyses were performed. XPS confirms a high degree of carbonization and the presence of oxygen and nitrogen containing functional groups by the prominent sp -carbon peak at 284.6 and in the C1s eV. Most importantly, the N1s area shows a prominent signal at 399.8 eV stemming from pyrrolic/imidazolic N and two minor peaks at 398.5 and 401.5 eV typical for pyridinic and graphitic N, respectively (Figure ). Among the nitrogen functionalities, the pyrrolic/imidazolic species amount to 61 %. This composition is independent of the addition of the foaming agent as it is also observed for the pure LPO2-Ade380 (Figure ).