Selective conversion of CO2 to C2H6 in pure water photocatalyzed by fluorobenzene-linked perylene diimide

Photochemical CO₂ conversion to valuable C₂ products is desirable but challenging due to high C-C coupling barriers. This study constructs an acceptor-donor-acceptor type N, N'-bis(4-fluorophenyl) perylene-3,4,9,10-bis(dicarboximide)-supramolecular photocatalyst for efficiently and selectively photo-converting CO₂ and water vapor into C₂H₆, achieving a high production rate of 124.84 μmol g^-1 h^-1 with 85% selectivity under continuous 50-hour illumination. The performance is mainly attributed to giant internal electric field induced by the incorporation of fluorobenzene into the perylene diimide framework, greatly enhancing the separation and transfer of photogenerated charges. Theoretical calculations further elucidate the critical role of fluorobenzene in lowering the activation energy of the reaction and promoting the formation of the key C-C coupling intermediate (*COCO). This work provides insight for the design of high-performance catalysts for CO₂ photoreduction.