than amine-impregnated silica (1.1 -1.7 J/g.K) such that it can act as a heat sink, further delaying bulk heating. In other words, additional energy is necessary to desorb the same amount of CO2 in humid gas streams, as exemplified by Wurzbacher who measured a 30% CO2 desorption energy increase between a 20% relative humidity (RH) to a 80% RH gas stream. Since the main difference between photo-swing and temperature-swing desorption lies in local vs. bulk heating, we hypothesize that the presence of water and range of the applied heat impacts the tradeoff between increased polymer mobility (plasticity and CO2 capacity) and induced heat "resistance". Consistent with other studies using PEI, the presence of H2O also affects the photo-swing CO2 desorption kinetics. The difference in the CO2 desorbed in dry and humid conditions is more pronounced for prolonged light exposures as inferred by Figure . While in dry flow, the peak CO2 desorption is reached within the first minute of heat or light applied, in the humid system, CO2 desorption seems to be slower, to exhibit multiple desorption events, and to require close to 2 minutes to reach maximum desorption levels. In the photo-swing process, the trace in Figure hints to more features, which could be related to localized heating desorbing H2O heterogeneously throughout the samples. Introducing a mechanical shutter mechanism between the LED and the sample, a continuous flow of dry 400 ppm CO2 gas stream was exposed to the sample for 33 hours, allowing for the measurement of > 90 photo-swing adsorption-desorption cycles over the TiN. Figure shows the CO2 evolution during cycle 83 and 93 that are representative of the other cycles during this experiment. The difference of 2.4 vs 2.18 mmol CO2/g PEI recorded during the photo-desorption step in Figure and Figure , respectively in the same experimental conditions is mainly attributed to the slight differences in LED alignment for the two sets of experiments, since photo-activated systems are very sensitive to alignment and focus, as can be