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

• Immobilizing perovskite CsPbBr3 nanocrystals on black phosphorus sheets is obtained. • CsPbBr3/BP acts as a new and effective photocatalyst for CO2 photoreduction. • Introduced BP trapps the electrons from CsPbBr3 for boosting charge separation. • Introduced BP in CsPbBr 3 generates more active sites to CO 2 activation and reduction. Direct conversion CO 2 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 (CsPbBr 3) immobilized on two-dimensional (2D) black phosphorus nanosheets (BP), resulting in a new and effective CsPbBr 3 /BP photocatalyst for CO 2 photoreduction. Compare to pristine CsPbBr 3 , the introduction of BP generates more active sites for facilitating CO 2 activation and trapped the excited electrons from CsPbBr 3 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 CO 2 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. [ABSTRACT FROM AUTHOR]