Porous organic polymers containing organic photosensitizer and metal-terpyridine molecules for efficient aqueous CO2 photoreduction

The development of photocatalysts with high efficiency and good selectivity under mild conditions, particularly in 100% aqueous medium, represents a critical avenue for the resourceful utilization of CO₂. In this work, 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene and 10-(4-([2,2':6',2''-terpyridin]-4'-yl)phenyl)-10H-phenothiazine were employed as monomers to synthesize three porous organic polymers (denoted as SFOP, NiOP, and ZnOP). These amorphous polymers were applied for the photoreduction of CO2 to CO in the absence of organic solvent. Compared to negligible CO generation of monomers, these polymers are all effective in aqueous CO2 photoreduction. Additionally, NiOP displayed the highest CO yield (731.3 μmol g⁻¹) and selectivity (94.6%) due to more efficient electron transfer process. These results have demonstrated that regulating metals in porous organic polymers enables the optimization of their catalytic performance.