Photoelectron Transfer Mediated by the Interfacial Electron Effects for Boosting Visible-Light-Driven CO2 Reduction

Imine-linked covalent organic frameworks (COFs) are popular candidates for photocatalytic CO2 reduction, but high polarization of the imine bond is less efficient for pi-electron delocalization between the linked building units, leading to low intramolecular electron transfer and poor photocatalytic efficiency. Herein, we present a structural and electronic engineering strategy through integrating the imine-linked COF consisting of Zn-porphyrin and Co-bipyridyl units with cadmium sulfide (CdS) nanowires to form a CdS@COF core-shell structure. The experimental and theoretical results have validated that CdS serves as the electron transfer channel through the interfacial electron effects, which induces photoelectron transfer from Zn-porphyrin to CdS and subsequent injection into Co-bipyridyl units for CO2 reduction. The as-prepared CdS@COF generates 4057 mu mol g(-1) CO in 8 h under visible-light irradiation, which is considerably higher than those of its neat CdS and imine-linked COF counterparts. This work provides protocols to tackle intramolecular charge transfer across polar linkages between photosensitizers and active sites for solar-to-chemical energy conversion.