Metal-free heterostructured 2D/1D polymeric carbon nitride/fibrous phosphorus for boosted photocatalytic hydrogen production from pure water

Elemental red phosphorus, including fibrous phosphorus (FP), is considered as promising metal-free visible-light-driven photocatalyst, yet the photocatalytic hydrogen production activity is relatively limited by the poor charge separation efficiency and sluggish charge carrier mobility. In this work, a two-dimensional (2D) polymeric carbon nitride (PCN) nanosheets were used to immobilize one-dimensional (1D) FP nanoribbons, creating a 2D/1D PCN/FP heterostructure through a facile electrostatic self-assembly approach. The optimal PCN/FP(0.2) heterostructure exhibited dramatically improved hydrogen production activity of 13.2 μmol∙h−1 under visible light irradiation, which is about 26.4 and 2.7 times higher compared with pristine PCN and FP photocatalysts, respectively. The introduction of red-colored FP could extend the optical harvesting of the PCN/FP heterostructure in the broad visible light region. Additionally, the formation of strong chemical P-N bonds between FP NRs and PCN NSs served as charge transfer channel that accelerated the migration of photoexcited charge carriers via direct Z-scheme pathway. The synergistically enhanced light absorption capacity and improved electron-holes separation efficiency in the PCN/FP heterostructure resulted in boosted photocatalytic hydrogen production performances. This study presents an alternative approach for designing and creating earth abundant metal-free heterostructures for photocatalysis applications.