Active sites modulation with Runge-Gross theorem: CO2 capture by porphyrinic metal-organic frameworks at excited states

Traditionally chemical modifications altering molecular skeletons (MSs) were the only solution to modulate material active sites at ground states. According to Runge-Gross theorem, the MS and the adjoint electron-configuration (MS-AEC) can be tuned at excited states (ESs), even without chemical modifications. A porphyrinic metal-organic framework PCN-222 and its metalloporphyrin homologs are used for adsorptive carbon capture both at ground states and with photoexcitation (350-780 nm). Instead of passive photothermal effects, the carbon capture performances of all the adsorbents get promotions. The dominant first ESs with long lifetimes meet the time-scale of molecular adsorption equilibrium, meanwhile tune the MS-AEC of the porphyrin ligands to generate new active sites with much more negative electrostatic-potentials, of which the distribution gradient is crucial for inducing CO2 and can be further modulated by the central-coordinated metal cations at ground and excited states. This work demonstrates the availability of static ESs and possibility of nonchemical modifications.