Metal–Salen-Incorporated conjugated microporous polymers as robust artificial leaves for solar-driven reduction of atmospheric CO₂ with H₂O

Abstract

Exploration of efficient and stable photocatalysts to mimic natural leaves for the conversion of atmospheric CO₂ into hydrocarbons utilizing solar light is very important but remains a major challenge. Herein, we report the design of four novel metal–salen-incorporated conjugated microporous polymers as robust artificial leaves for photoreduction of atmospheric CO₂ with gaseous water. Owing to the rich nitrogen and oxygen moieties in the polymeric frameworks, they show a maximum CO₂ adsorption capacity of 46.1 cm³ g^–1 and adsorption selectivity for CO₂/N₂ of up to 82 at 273 K. Under air atmosphere and simulated solar light (100 mW cm^–2), TEPT-Zn shows an excellent CO yield of 304.96 µmol h^–1 g^–1 with a selectivity of approximately 100%, which represents one of the best results in terms of organic photocatalysts for gas-phase CO₂ photoreduction so far. Furthermore, only small degradation in the CO yield is observed even after 120-h continuous illumination. More importantly, a good CO yield of 152.52 µmol g^–1 was achieved by directly exposing the photocatalytic reaction of TEPT-Zn in an outdoor environment for 3 h (25–28°C, 52.3 ± 7.9 mW cm^–2). This work provides an avenue for the continued development of advanced polymers toward gas-phase photoconversion of CO₂ from air.

Keywords

air atmosphere / artificial leaf / CO₂ photoreduction / conjugated microporous polymers / metal–salen