After capture from each of the three test concentrations (100%, 3.8%, 400 ppm), we rested the system in the dark for 90 min under a static N2 headspace. As indicated also by the UV-vis absorption profile, during this time, the fluorenyl cation was gradually and completely quenched, recovering the carbinol. Thus, we considered it likely that that the captured CO2 was fully released during the process.