Hetero-phase dendritic elemental phosphorus for visible light photocatalytic hydrogen generation

We demonstrate a carefully tailored elemental red phosphorus (red P) for a record-high photocatalytic hydrogen evolution rate of 1280 μmol g −1 h −1 . This performance has even surpassed some of the established compound photocatalysts. Systematic studies reveal that the bismuth-catalyzed selective growth of the preferential crystal phases of red P leads to the formation of fibrous and Hittorf’s phases at distinctive sites within the same photocatalyst particle of dendritic morphology: nanobranches of fibrous phase and main stems of Hittorf’s phase. As each crystal phase possesses unique band energy potential, the intimate heterojunction between the two phases affords an effective built-in driving force for the efficient transportation of photoexcited charge carriers with suppressed charge trapping and recombination. The strategy in crystal phase engineering of red P as well as the understanding of its charge transportation properties in this work provides new insights into developing favorable elemental P-based materials for various photocatalytic applications. A pure Hittorf-fibrous hetero-phase elemental red P system with favorable dendritic architecture was constructed by a bismuth-assisted chemical-vapor-deposition strategy. The “stem-branch” heterojunction facilitated effective charge separation by restricting the self-charge trapping and charge recombination processes within the dendritic red P, resulting in a record high visible light hydrogen evolution rate of 1280 μmol g −1 h −1 . • Dendritic red P (DRP) is prepared by a Bi-assisted CVD strategy. • DRP shows a record high visible light photocatalytic H 2 evolution activity. • The hetero-phase junction is attributed to the improved photoactivity of DRP. • Charge dynamics is revealed by ultrafast time-resolved spectroscopy.