Tunable photodynamic switching of DArE@PAF-1 for carbon capture

A new type of photodynamic carbon capture material with up to 26 wt CO2 desorption capacity is synthesized via incorporation of diarylethene (DArE) as guest molecules in porous aromatic framework-1 (PAF-1). In these host-guest complexes, the carboxylic acid groups featured in DArE allow multiple noncovalent interactions to exist. DArE loadings ranging from 1 to 50 wt are incorporated in PAF-1 and the complexes characterized by UV-vis spectroscopy, FT-IR spectroscopy, CO2, and N2 adsorption. Successful inclusion of DArE in PAF-1 is indicated by the reduction of pore size distributions and an optimum loading of 5 wt is determined by comparing the percentage photoresponse and CO2 uptake capacity at 1 bar. Mechanistic studies suggest that photoswitching modulates the binding affinity between DArE and CO2 toward the host, triggering carbon capture and release. This is the first known example of photodynamic carbon capture and release in a PAF. Dynamic light-activated carbon capture and release in porous aromatic framework-1 (PAF-1) is achieved by successfully loading diarylethene (DArE) as a guest molecule. Up to 26 wt CO2 desorption capacity is possible with 50 wt DArE loading. The observed photodynamicity occurs because of host-guest competition between DArE and CO2 inside the sterically hindered pores of PAF-1.