A metal–free porous organic polymer with high CO2 adsorption for robust aqueous CO2 photoreduction via molecular regulation

Development of photocatalysts with both high CO 2 adsorption capacity and robust CO 2 reduction performance is promising toward carbon capture and utilization (CCU). Herein, a porous organic polymer (POP) based on molecular monomers 1,2,3,5–Tetrakis(carbazol–9–yl)–4,6–dicyanobenzene (4CzIPN) and 9–(4–([2,2′:6′,2′'–terpyridin]–4′–yl)phenyl)–9H–carbazole (CzTPY) has been prepared for metal–free photocatalytic reduction of CO 2 to CO with 94.7% selectivity in 100% aqueous medium. The POP displays a yield of CO up to 265.7 mmol g –1 , which is among the highest yields for POPs–based photocatalytic systems. More importantly, the POP also shows a high CO 2 uptake of 109.1 cm 3 g –1 (21.4 wt%) at 273 K and 1 atm. External photosensitizers or catalysts are not required in this photocatalytic system. Mechanistic studies indicate the introduction of CzTPY improved the electron transfer and charge separation. These results show a feasible way to construct POP–based photocatalysts not only capturing CO 2 efficiently but also catalyzing CO 2 reduction with a high yield by rational regulation of molecular monomers.