Direct S-scheme 0D/2D photocatalyst of CsPbBr3 quantum dots/BiVO4 nanosheets for efficient CO2 photoreduction

Abstract

The development of novel, efficient and stable catalysts for CO2 photoreduction is highly anticipated. In this work, a series of 0D/2D CsPbBr3/BiVO4 composites were prepared by simple self-assembly of 0D CsPbBr3 quantum dots and 2D BiVO4 nanosheets. It was discovered that the photocatalytic CO2 reduction activities of as-prepared CsPbBr3/BiVO4 catalysts were greatly improved when exposed to visible light. For the optimal sample, the average CO production could achieve 41.02 μmol·g−1·h−1, and the photocatalytic performance is 7 and 4 times that of original BiVO4 and CsPbBr3, respectively. Additionally, the sample exhibited high stability in the cycle test. According to the comprehensive characterization test and analysis results, the enhanced CO2 photoreduction performances are attributed to the composites' increased light absorption capacity and noticeably accelerated charge carrier separation and transfer efficiency. The special S-scheme photocatalytic mechanism of CsPbBr3/BiVO4 hybrids is proposed and discussed in detail on the basis of the electron spin resonance results and the energy band structure theory. This work provides new opportunities for designing S-scheme heterojunctions based on lead halide perovskite with high photocatalytic activity.