Average desorption quantities for three consecutive cycles were measured for dry and humid photo and thermal desorption and summarized in Table . In dry conditions, the thermal desorption is more effective than photo-driven desorption, which is expected since the LED only illuminates the bottom part of the sample compared to bulk heating of the entire sample when immersed in the oil bath. Considering that only half of the sample was illuminated, it is impressive that photo-desorbed CO2 reached 80% of the thermally desorbed quantity, which we attribute to the high thermal conductivity of TiN (22-29 W/m.K) enabling efficient heat conduction throughout the bulk sample. In humid gas flow settings, photo-swing desorption outperformed the thermal desorption, while, surprisingly, the CO2 thermal-swing capacity in humid condition is lower than in dry conditions. This observation is characteristic of the DAC cycling times that are far from thermal equilibrium. For example, Russel-Parks and co-authors showed that PEI's mobility requires 60-90 min to equilibrate in humid CO2 conditions, which is far from the 15 min used in DAC. Under our simulated DAC conditions, the role of humidity can be at least two-fold. First, it is known that H2O stabilizes carbamate species, thereby freeing an amine binding site for additional interaction with CO2, such that a two-fold increase in CO2 capacity is, in principle, possible in the presence of H2O. Because of this binding mechanism, the presence of H2O also prevents the high degree of polymer crosslinking that occurs in dry conditions linked to a higher polymer mobility than in dry conditions. Additionally, water has a higher heat capacity (4.2 J/g.K)