Immobilizing perovskite CsPbBr3 nanocrystals on Black phosphorus nanosheets for boosting charge separation and photocatalytic CO2 reduction

Direct conversion CO2 to useful chemical fuels by photocatalysis has been considered to be a promising strategy for renewable energy production. The realization of this goal relies mainly on the development of photocatalysts with ideal charge separation efficiency. Here, we use all-inorganic perovskite nanocrystals (CsPbBr3) immobilized on two-dimensional (2D) black phosphorus nanosheets (BP), resulting in a new and effective CsPbBr3/BP photocatalyst for CO2 photoreduction. Compare to pristine CsPbBr3, the introduction of BP generates more active sites for facilitating CO2 activation and trapped the excited electrons from CsPbBr3 with high charge separation efficiency. Time-resolved photoluminescence and transient absorption measurements together with density functional theory calculations provide a clear elucidation of the charge separation pathways that contribute to the enhanced CO2 conversion rate. This significant feature provides a new venue for constructing all-inorganic perovskite-based photocatalyst by combining with BP for solar energy conversion and artificial photosynthesis.