Precisely modulate interfacial Bi-O bridge bond in Co-TCPP/Bi3O4Br to trigger long-lasting charge separation for boosting CO2 photoreduction

Abstract

Insufficient charge separation and feeble CO2 activation limit the CO2 photoreduction efficiency. It is highly desirable to consciously construct organic–inorganic hybrid composites to simultaneously accelerate charge separation and provide favorable active sites. Herein, a defect-induced interfacial Bi-O bridge bond is constructed by grafting terminal O of cobalt porphyrin (Co-TCPP) with Bi3O4Br. Systematic investigations reveal that the Bi-O bridge bond as the charge migration bridge accelerates the extraction and transfer of electron from the external [Bi3O4] layers to Co-TCPP, and the millisecond separation lifetime of electrons on Co-TCPP can be achieved. Co atoms as the active sites optimized the CO2 adsorption and activation, thus promoting the formation of COOH*. As a result, the CO2 photoreduction rate of 0.5% Co-TCPP/Bi3O4Br reaches 71.3 μmol g-1h-1 in pure water, 2.53-fold of that on the pristine Bi3O4Br. This work provides atomistic insights and strategies for the construction of new organic–inorganic hybrid materials for artificial photosynthesis and CO2 photoreduction.