Adsorptive carbon capture performances of porous carbon improved by photoinduction

Porous carbon (PC) is a superior sorbent for carbon capture, whereas the CO₂ adsorption ability of an already formed PC with fixed pore structures and adsorption sites is difficult to be optimized. In this study, a mechanism based on photoexcitation that can universally improve the carbon capture ability of already formed PCs is discovered. With a small amount of TCP-coordinated-copper [TCP = 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin] nanosheet films loaded, a commercial PC derived from sawdust can be largely improved in terms of CO₂ adsorption performances, especially under the illumination of 420 nm. The original CO₂ adsorption capacity (0 °C, 1 bar) of the PC is 2.81 mmol g⁻¹, while that of the treated PC is elevated to 4.56 mmol g⁻¹ under the illumination of 420 nm, increased by 62 %. A new kind of CO₂ adsorption site is formed on the treated PC, which can be photo-excited to vertically alter the electron density distribution (EDD) of the PC surface. It is proved that promoting the N₂ desorption, the altered EDD can interact with the CO₂ and stabilize it more, which results in the CO₂ adsorption capacity and selectivity remarkably improved.