Step-Scheme Photocatalyst of CsPbBr3 Quantum Dots/BiOBr Nanosheets for Efficient CO2 Photoreduction.

ABSTRACT

Heterojunction manipulation has been deemed as a promising approach in exploring efficient photocatalysts for CO2 reduction. In this article, a novel step-scheme (S-scheme) photocatalyst of CsPbBr3 quantum dots/BiOBr nanosheets (CPB/BiOBr) was fabricated via a facile self-assembly process. The strong interaction, staggered energy band alignments, and much different Fermi levels between CsPbBr3 and BiOBr promised the formation of an S-scheme heterojunction. The resultant CPB/BiOBr heterojunction delivered remarkable photocatalytic performance in CO2 reduction, with an electron consumption rate of 72.3 µmol g-1 h-1, which was 4.1 and 5.7 times that of single CsPbBr3 and BiOBr, respectively. The superior photocatalytic performance originated from the impactful spatial separation of photoinduced electron-hole pairs, as well as the preservation of strongly reductive electrons for CO2 reduction. This work offers a rational strategy to design S-scheme heterojunctions based on lead halide perovskites, which are expected to have potential applications in the field of photocatalysis and solar energy utilization.