Constructing metal-free heterophotocatalyst using two-dimensional carbon nitride sheets and violet phosphorene for highly efficient visible-light photocatalysis

Two-dimensional(2D)carbon nitride sheets(CNs)with nanoscale thickness have great potential in solar energy conversion owing to their intrinsic bandgap.However,their photocatalytic efficiency falls far below the practical requirements because the generated electron-hole pairs rapidly recombine.We construct a metal-free 2D p–n junction heterophotocatalyst from CNs and violet phosphorene(VP)using a simple electrostatic self-assembly method.The experimental results and density functional theory calculations show that the built-in electric field of the p–n junction promotes photogenerated carrier transport at the heterojunction interface,thereby promoting the separation of photogenerated electron-hole pairs.Under visible-light illumination,the visible-light photocatalytic hydrogen and CO production rates of the CNs/VP heterojunction were increased by 5.85 and 1.51 times,respectively,when compared to that of CNs.This study provides new insights into the design of metal-free heterogeneous photocatalysts with high catalytic activity。