Transforming CO₂ into formic acid by integrated solar-driven catalyst-enzyme coupled artificial photosynthetic system

Photo-biocatalyst coupled systems offer a promising approach for converting solar energy into valuable fuels. The bio-integrated photocatalytic system sets a research benchmark by utilizing green energy for formic acid production, reducing CO₂ emissions, and enhancing selectivity through bio-enzyme incorporation. This bio-photocatalytic are promising solutions for environmental remediation and energy production. This research reports the synthesis and application of a novel metal-free, nitrogen-enriched graphene composite photocatalyst (N_enGCTPP) for artificial photosynthesis. N_enGCTPP was synthesized by covalently coupling tetraphenyl porphyrin tetracarboxylic acid (TPP) with N-doped graphene via a polycondensation pathway. The photogenerated charge separation then facilitates the regeneration of enzymatically active coenzymes (NADH) for formic acid production catalyzed by formate dehydrogenase. The photocatalyst exhibited remarkable performance in photocatalytic regeneration of the coenzyme NADH from NAD⁺ with a high yield of 41.80%, as well as photocatalytic production of formic acid (HCO₂H) as a solar fuel from CO₂ with a yield of 99.12 μM. This innovative artificial photosynthetic system demonstrates an affordable, highly efficient, and selective approach for converting carbon dioxide into valuable solar fuels and regenerating NADH, addressing environmental concerns and contributing to sustainable energy solutions.