A mechanochemically prepared graphdiyne (CnH2n−2) based Cu3P@GDY p–n heterojunction for efficient photocatalytic hydrogen evolution

Abstract

As an allotrope of carbon, graphdiyne (C_nH_2n−2, GDY) is a two-dimensional carbon net structure composed of sp and sp² hybrids. GDY has received a lot of attention because of its excellent electrical conductivity, adjustable electronic structure and special electron transfer enhancement performance. It has great potential in the field of hydrogen evolution by photocatalytic water splitting due to its special properties. Here, GDY is successfully prepared by means of mechanochemical coupling of the precursor C₆Br₆ with CaC₂ through a ball-milling approach. Through simple physical mixing, the p-type Cu₃P semiconductor and n-type GDY semiconductor are tightly coupled to prepare a Cu₃P@GDY composite photocatalyst with a p–n heterojunction structure. The built-in electric field at the p–n interface provides a fast electron transport channel, which greatly promotes charge transfer and enables more efficient separation and a lower recombination rate of photogenerated carriers in the composites. Therefore, the composite photocatalyst Cu₃P@GDY exhibits the most significant photocatalytic hydrogen evolution characteristics compared to the single component.