Band-Gap and Charge Transfer Engineering in Red Phosphorus-Based Composites for Enhanced Visible-Light-Driven H2 Evolution

It is known that the low lifetime of photogenerated carriers is the main drawback of elemental photocatalysts. Therefore, a facile and versatile one-step strategy to simultaneously achieve the oxygen covalent functionalization of amorphous red phosphorus (RP) and in situ modification of CdCO3 is reported. This strategy endows RP with enhanced charge carrier separation ability and photocatalytic activity by coupling band-gap engineering and heterojunction construction. The as-prepared nCdCO3 /SO-RP (n=0.1, 0.25, 0.5, 1.0) composites exhibited excellent photocatalytic H2 evolution activity (up to 516.3 μmol g-1 h) from visible-light-driven water splitting (λ>400 nm), which is about 17.6 times higher than that of pristine RP. By experimental and theoretical investigations, the roles of surface oxygen covalent functionalization, that is, prolonging the lifetime of photogenerated carriers and inducing the negative shift of the conduction band potential, were studied in detail. Moreover, the charge transfer mechanism of these composites has also been proposed. In addition, these composites are stable and can be reused at least for three times without significant activity loss. This work may provide a good example of how to promote the activity of elemental photocatalysts by decorating their atomic structure.