▎ 摘　　要

NOVELTY - Preparing purple phosphorus/graphene composite material comprises (i) preparing graphene on the surface of the copper foil sample; placing the copper foil sample loaded with graphene into the etching liquid for etching; after the copper in the copper foil sample is completely etched, transferring the graphene to de-ionized water for cleaning, then transferring the graphene to the substrate; and (ii) stripping the block-shaped purple phosphorus crystal by physical method to obtain purple phosphorus, and transferring the purple phosphorus to the graphene surface of the substrate of step (i), and forming purple phosphorus/graphene composite material. USE - The composite material is useful as gas sensor (claimed). ADVANTAGE - The method constructs heterojunction between two materials, provides electron by graphene, provides adsorption site by purple phosphorus, and improves the resistance change by more than 30 times the original, is safe and pollution-free, and can finish the preparation process in the open environment at room temperature and atmospheric pressure.