▎ 摘　　要

NOVELTY - Single layer graphene/gold nano -particle composite material comprises (in wt.%) gold nano-particle (50) and single layer graphene (50-72). USE - The composite material is useful: for detecting harmful gases; and in biological detection field. ADVANTAGE - The method to prepare composite material utilizes simple preparation procedures, has less requirement of device, and prevents the pollution caused by using organic matter, thus it is environmental-friendly. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing the composite material, comprising (i) taking potassium permanganate and concentrated sulfuric acid as oxidant in the mass ratio of 1:10-1:20, where the amount of oxidant added accounts to 37.5-74 g/g of graphite, stirring, maintaining the reaction temperature to 5-15 degrees C, and the reaction time to 0.5 hours at 1.5 degrees C, continuously stirring, increasing the temperature to 20-25 degrees C, where the reaction time is 1.5-2.5 hours, and then adding distilled water, adding hydrogen peroxide till the color of the solution changes without any bubbles, controlling the reaction temperature to lower than 100 degrees C, and filtering to obtain a monolayer oxidized graphene; (ii) taking the single layer graphene oxide solution of dry powder of monolayer graphene oxide powder, then adding water to chloroauric solution (0.005-0.015%), adding single layer graphene oxide powder (5-50 ml/mg), allowing to stand for 20-40 minutes, adding sodium citrate or sodium borohydride as reducing agent, adding single layer graphene oxide powder 100-500 mu l/mg, heating, and stirring simultaneously, where the reaction temperature is 60-85 degrees C, and reaction time is 1-2 hours to obtain graphene/gold nano-particle composite material; and (iii) centrifuging the obtained turbid liquid to obtain a precipitate, and obtaining the product.