2D-C 3 N 4 encapsulated perovskite nanocrystals for efficient photo-assisted thermocatalytic CO 2 reduction.

Very recently, halide perovskites, especially all-inorganic CsPbBr 3 , have received ever-increasing attention in photocatalysis owing to their superior optoelectronic properties and thermal stability. However, there is a lack of study on their application in thermocatalysis and photo-thermocatalysis. Herein, we rationally designed a core-shell heterojunction formed by encapsulating CsPbBr 3 nanoparticles with the 2D C 3 N 4 (m-CN) layer via a solid-state reaction (denoted as m-CN@CsPbBr 3 ). A series of experiments suggest that abundant adsorption and active sites of CO 2 molecules as well as polar surfaces were obtained by utilizing m-CN-coated CsPbBr 3 , resulting in significant improvement in CO 2 capture and charge separation. It is found that the m-CN@CsPbBr 3 effectively drives the thermocatalytic reduction of CO 2 in H 2 O vapor. By coupling light into the system, the activity for CO 2 -to-CO reduction is further improved with a yield up to 42.8 μmol g -1 h -1 at 150 °C, which is 8.4 and 2.3 times those of pure photocatalysis (5.1 μmol g -1 h -1 ) and thermocatalysis (18.7 μmol g -1 h -1 ), respectively. This work expands the application of general halide perovskites and provides guidance for using perovskite-based catalysts for photo-assisted thermocatalytic CO 2 reduction.