▎ 摘　　要

NOVELTY - Producing silver nanosheet-graphene composite material comprises (i) mixing polyethyleneimine solution and graphene oxide, reacting at 60-100 degrees C for 6 hours, washing with deionized water to obtain graphene, and ultrasonically dispersing the graphene in water to prepare colloid solution; and (ii) adding silver nitrate, sodium citrate, hydrogen peroxide and sodium borohydride to the graphene colloid solution at 20-30 degrees C to obtain the mixed solution, stirring and reacting the mixed solution for 5-60 minutes at 20-30 degrees C under dark conditions, centrifuging and removing supernatant. USE - The composite material is useful for modifying working electrode for electrochemical detection of trace amounts of hydrogen peroxide, sodium nitrite and hydrazine hydrate (all claimed). ADVANTAGE - The composite material has high stable performance. DETAILED DESCRIPTION - Producing silver nanosheet-graphene composite material comprises (i) mixing polyethyleneimine solution and graphene oxide of mass ratio 2.5-5:1, reacting at 60-100 degrees C for 6 hours in a polytetrafluoroethylene-lined stainless steel reaction kettle, washing with deionized water to obtain graphene, and ultrasonically dispersing the graphene in water to prepare colloid solution with graphene content of 24-50 mu g/ml, where the weight percentage of polyethyleneimine solution is 40-50% of the solution; and (ii) adding silver nitrate, sodium citrate, hydrogen peroxide and sodium borohydride to the graphene colloid solution at 20-30 degrees C to obtain the mixed solution, stirring and reacting the mixed solution for 5-60 minutes at 20-30 degrees C under dark conditions, centrifuging and removing supernatant to obtain the silver nanosheet-graphene composite material, where silver nitrate content in the mixed solution is 10-25 mu g/ml, sodium citrate content is mu g/ml, hydrogen peroxide content is 500-1200 mu g/ml and sodium borohydride content is 20-60 mu g/ml. An INDEPENDENT CLAIM is also included for the silver nanosheet-graphene composite material prepared by the above method, where the silver nanosheet is uniformly loaded on the surface of the graphene, the silver nanosheet exhibits triangular and hexagonal sheet shaped structure, the size of the sheet is 50-200 nm and the loading amount of the silver nanosheet is 10-40%.