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

Abstract

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 Fe^III-porphyrin-modified capsule. Pre-incubation of Ir(ppy)₃ with BIH produces an elevated concentration of anionic Ir^II(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.