Using the same sample, three breakthrough cycles were subsequently carried out in succession, involving adsorption of compressed air streams with relative humidity levels of 25%, 50%, 75%, and 100% and regeneration with heating at 150 °C under He (see Figures ). Notably, there was no significant change in the measured breakthrough times over the course of the 15 adsorption runs (Figure ), and no change in the corresponding material capacity (Figures and and Table ). Indeed, the measured average O2 capacity from triplicate measurements under dry conditions was the same within error as that measured at the highest humidity (Figure ), indicating that water neither hinders the material performance nor competes with O2 for binding at the copper(I) sites (Table ). Finally, after the third breakthrough run at 100% relative humidity, two additional breakthrough cycles at the same relative humidity were performed with more mild regeneration under flowing He at only 50 °C (Figure ). Although some water remains adsorbed in the material following desorption under these conditions (see Figure ), there was no apparent change in the material capacity. Of note, the O2 and N2 capacities averaged over all 17 runs (1.17 (7) and 1.7(3) mmol/g, respectively) indicate an enhancement in the quantity of O2 in the adsorbed phase relative to ambient air.