Highly Efficient Photocatalytic Reduction of CO2 to CO by In Situ Formation of a Hybrid Catalytic System Based on Molecular Iron Quaterpyridine Covalently Linked to Carbon Nitride

Efficient and selective photocatalytic CO2 reduction was obtained within a hybrid system that is formed in situ via a Schiff base condensation between a molecular iron quaterpyridine complex bearing an aldehyde function and carbon nitride. Irradiation (blue LED) of an CH3CN solution containing 1,3‐dimethyl‐2‐phenyl‐2,3‐dihydro‐1H‐benzo[d]imidazole (BIH), triethylamine (TEA), Feqpy‐BA (qpy‐BA=4‐([2,2′:6′,2′′:6′′,2′′′‐quaterpyridin]‐4‐yl)benzaldehyde) and C3N4 resulted in CO evolution with a turnover number of 2554 and 95 % selectivity. This hybrid catalytic system unlocks covalent linkage of molecular catalysts with semiconductor photosensitizers via Schiff base reaction for high‐efficiency photocatalytic reduction of CO2, opening a pathway for diverse photocatalysis. A covalent‐linked C3N4‐aldehyde‐decorated iron quaterpyridine hybrid catalyst was initially developed by in situ Schiff base reaction, achieving high CO generation and selectivity for photocatalytic CO2 reduction. The enhanced catalytic performance is mainly attributed to the accelerated photoinduced electron transfer and utilization via the formed covalent linkage.