Merging bioinspired incubation with supramolecular photocatalysis for Michaelis CO2 reduction beyond enzymes

The conversion of carbon dioxide into chemicals and fuels via photoreduction offers a promising path toward a sustainable and carbon-neutral future, but the low concentration of photosensitized reactive species and their associated sluggish kinetics limit energy conversion. Herein, a bioinspired incubation strategy is developed to pretreat an artificial cofactor 1,3-dimethyl-2-phenyl-2,3-dihydrobenzimidazole (BIH) with a photocatalyst, enriching reactive species within an FeIII-porphyrin-modified capsule. Pre-incubation of Ir(ppy)3 with BIH produces an elevated concentration of anionic IrII(ppy)3 species, which are abstracted into the cationic capsule to enable a saturated enzymatic conversion of CO2-to-CO. This photocatalytic system achieves a turnover number of 180,000 and a turnover frequency of 165 s−1 for CO production, comparable to the reported most effective photocatalytic CO2-to-CO systems and typical CO2 reductases. This pseudo-enzymatic transformation allows concurrent intramolecular cyclic dehydrogenation of imines and CO2 reduction. Here, we show an opportunity for facilitating the conversion of high-energy-barrier photocatalysis under mild conditions. A bioinspired pre-incubation strategy enriches reactive species within a synthetic iron-porphyrin capsule, enabling CO2-to-CO conversion with TOF of 165 s−1 and TON of 180,000, competing with natural enzymes and reported photocatalysts.