Visible-light driven boosting electron-hole separation in CsPbBr3 QDs@2D Cu-TCPP heterojunction and the efficient photoreduction of CO2.

ABSTRACT

CsPbBr3 quantum dots (CPB QDs) have great potential in photoreduction of CO2 to chemical fuels. However, the low charge transportation efficiency and chemical instability of CPB QDs presents a considerable challenge. Herein, we describe the electrostatic assemblies of negatively charged colloidal two dimensional (2D) Cu-Tetrakis(4-carboxyphenyl) porphyrins (Cu-TCPP) nanosheets and positively CPB QDs to construct the hydride heterojunction. The photogenerated electron migration from CPB QDs to Cu-TCPP nanosheets has been witnessed, providing the supply of long-lived electrons for the reduction of CO2 molecules adsorbed on Cu-TCPP matrix. As a direct result, The CPB@Cu-TCPP-x (x wt% of CPB QDs) photocatalysts exhibit significantly enhanced photocatalytic conversion of CO2, compared to the parent Cu-TCPP nanosheets or single CPB QDs. Especially, when with 20% CPB QDs, the heterostruture system achieves an evolution yield of 287.08 µmol g-1 in 4 h with highly CO selectivity (99%) under visible light irradiation, which is equivalent to a 3.87-fold improvement compared to the pristine CPB QDs. Meanwhile, the CH4 generation rate can be up to 3.25 µmol g-1. This optimized construction of heterostructure could provide a platform to funnel photoinduced electrons to the reaction center, which can both act as a crucial capture and the reaction actives of CO2.