Charge Carrier Dynamics of CsPbBr 3 /g-C 3 N 4 Nanoheterostructures in Visible-Light-Driven CO 2 -to-CO Conversion.

The photon energy-dependent selectivity of photocatalytic CO 2 -to-CO conversion by CsPbBr 3 nanocrystals (NCs) and CsPbBr 3 /g-C 3 N 4 nanoheterostructures (NHSs) was demonstrated for the first time. The surficial capping ligands of CsPbBr 3 NCs would adsorb CO 2 , resulting in the carboxyl intermediate to process the CO 2 -to-CO conversion via carbene pathways. The type-II energy band structure at the heterojunction of CsPbBr 3 /g-C 3 N 4 NHSs would separate the charge carriers, promoting the efficiency in photocatalytic CO 2 -to-CO conversion. The electron consumption rate of CO 2 -to-CO conversion for CsPbBr 3 /g-C 3 N 4 NHSs was found to intensively depend on the rate constant of interfacial hole transfer from CsPbBr 3 to g-C 3 N 4 . An in situ transient absorption spectroscopy investigation revealed that the half-life time of photoexcited electrons in optimized CsPbBr 3 /g-C 3 N 4 NHS was extended two times more than that in the CsPbBr 3 NCs, resulting in the higher probability of charge carriers to carry out the CO 2 -to-CO conversion. The current work presents important and novel insights of semiconductor NHSs for solar energy-driven CO 2 conversion.