Tunable Photodynamic Switching of DArE@PAF-1 for Carbon Capture

Abstract

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.