Amide-bridged conjugated organic polymers: efficient metal-free catalysts for visible-light-driven CO(2) reduction with H(2)O to CO

The visible-light-driven photoreduction of CO(2) to value-added chemicals over metal-free photocatalysts without sacrificial reagents is very interesting, but challenging. Herein, we present amide-bridged conjugated organic polymers (amide-COPs) prepared via self-condensation of amino nitriles in combination with hydrolysis, for the photoreduction of CO(2) with H(2)O without any photosensitizers or sacrificial reagents under visible light irradiation. These catalysts can afford CO as the sole carbonaceous product without H(2) generation. Especially, amide-DAMN derived from diaminomaleonitrile exhibited the highest activity for the photoreduction of CO(2) to CO with a generation rate of 20.6 μmol g(−1) h(−1). Experiments and DFT calculations confirmed cyano/amide groups as active sites for CO(2) reduction and second amine groups for H(2)O oxidation, and suggested that superior selectivity towards CO may be attributed to the adjacent redox sites. This work presents a new insight into designing photocatalysts for artificial photosynthesis.