▎ 摘　　要

NOVELTY - Preparing a molybdenum disulfide-graphene composite nanosheet comprises e.g. placing foamed nickel in quartz tube furnace, adding methane gas and cooling to obtain graphene-coated foam nickel, adding polymethyl methacrylate into ethyl lactate and stirring to obtain mixed solution, dripping the mixed solution in the sample gun and drying to obtain surface coated with polymethyl methacrylate foam graphene, cutting, soaking in hydrochloric acid solution to obtain nickel-removed three-dimensional foam graphene, which is soaking in acetone to obtain polymethylmethacrylate-removed foamed graphene. USE - The method is useful for preparing a molybdenum disulfide-graphene composite nanosheet. ADVANTAGE - The nanosheet has large specific surface area, good and efficient electrical conductivity and sensitive in detection of levodopa. DETAILED DESCRIPTION - Preparing a molybdenum disulfide-graphene composite nanosheet comprises (I) (i) placing the foamed nickel in center of quartz tube furnace under the protection of argon gas and hydrogen gas from room temperature to 20 degrees C/minute temperature, increasing the speed to 40 degrees C/minute, heating until the temperature is 1000-1100 degrees C, maintaining the temperature for 30-60 minutes, adding methane gas into the tubular furnace at 1000-1100 degrees C at a rate of 5-10sccm for 5-20 minutes, cooling the quartz tube furnace at a cooling rate of 80-100 degrees C/minutes from 1000-1100 degrees C and cooling to room temperature to obtain graphene-coated foam nickel, where the foamed nickel density is 420-440 g/m2, the thickness is 1.6-2 mm, the flow rate of the argon gas is 480-500 sccm, the flow rate of hydrogen is 180-200sccm; (ii) adding polymethyl methacrylate into ethyl lactate at 80-120 degrees C under the condition of heating and stirring for 1-2 hours to obtain mixed solution according to 100-200 mu l, dripping the mixed solution in the sample gun obtained by a graphene coated surface of foam nickel, naturally drying at room temperature, then at 150-200oc under the condition of the temperature insulation for 0.5-1 hour to obtain surface coated with polymethyl methacrylate foam graphene, where the mass fraction of methyl methacrylate in the mixed solution is 4-5%; and (iii) cutting the surface-coated polymethyl methacrylate foam graphene into cubes with a surface area of 0.5-2 cm2, soaking in 3-4 mol/l hydrochloric acid solution at 80-90 degrees C for 4-6 hours to obtain nickel-removed three-dimensional foam graphene , which is soaking in acetone at 60-70 degrees C for 0.5-1.5 hours to obtain polymethylmethacrylate-removed foamed graphene, cleaning the polymethylmethacrylate-removed foamed graphene with distilled water, passing to clean glass and freeze-drying to obtain foamed graphene; (II) (ii.a) adding molybdenum disulfide powder into a mixed solution of acetone and water (89:11v/v), in which the concentration of molybdenum disulfide after dissolving the molybdenum disulfide is 30 mgx ml-1, subjecting to ultrasonic dissociation using an ultrasonic processor, using the ultrasonic process to prevent overheating of the probe under a low-temperature cycle with a pulse duration of 20 seconds and 10 seconds and ultrasonic peeling time is 1-4 hours; (ii.b) centrifuging the ultrasonic peeled suspension of molybdenum disulfide nano-tablets at a centrifugal rate of 3000 rotations/minute for 30 minutes to obtain supernatant, placing the supernatant in an air drying oven for drying the molybdenum disulfide nano-sheets, dispersing in a vial with deionized water to obtain a concentration of 20mgx ml-1 molybdenum disulfide nanosheet suspension; and (III) (iii.a) adding the ultrasonically dispersed foamed graphene into deionized water at a concentration of 0.07 mgx ml-1, subjecting to ultrasonic treatment on the dispersion at 540 W using an ultrasonic processor to prevent overheating of the probe under low temperature cycling with 20 seconds to open 10 seconds off pulse with ultrasonic release time of 1-4 hours to obtain graphene suspension; and (iii.b) mixing 0.5ml molybdenum disulfide nanosheet and 19.5 ml graphene nanometer with suspension to obtain molybdenum disulfide-graphene composite nanosheets mixed solution with a concentration ratio of 9:1 and ultrasonically dispersing to obtain uniform suspension; and (IV) (iv.a) dissolving the indium tin oxide (ITO) conductive glass separately in acetone solution and ethanol solution, ultrasonically cleaning with deionized water for 20 minutes, naturally cooling and drying at room temperature, fixing six pieces of ITO conductive glass on the heating plate of the spraying equipment, covering the ITO conductive glass clamp on the side of the electrode wire with transparent tape to ensure the electrode wire and the ITO conductive glass; and (iv.b) placing the uniformly dispersed suspension of molybdenum disulfide-graphene composite nanosheets in a spray gun, and preparing the molybdenum disulfide-graphene composite nanocomposite by an automatic spraying method to obtain sheet-ITO electrode, where the entire spraying process is performed under a pressure of 10 psi, where the distance from the nozzle to the ITO conductive glass is 15 cm, the temperature of the heating plate is 110 degrees C, then spraying the molybdenum disulfide-graphene composite nanosheet, placing the ITO electrode in a quartz tube furnace, heating at a rate of 10 degrees C/minute-1 to 700 degrees C for 2 hours under the argon atmosphere of 400 sccm and cooling the furnace to room temperature.