▎ 摘　　要

NOVELTY - Preparation of graphene quantum dot using three-dimensional (3D) graphene as raw material includes cutting foamed nickel substrate, ultrasonically cleaning with absolute ethyl alcohol and deionized water to remove oil stain in surface, constant temperature heating in argon atmosphere and hydrogen atmosphere, sending methane gas, cooling to room temperature, obtaining 3D graphite/foamed nickel composite material, immersing in nitric acid solution, washing with deionized water, taking out, obtaining 3D graphene and dispersing in alcohol solvent. USE - Preparation of graphene quantum dot (claimed) used e.g. for lithium ion battery and photocatalysis. ADVANTAGE - The method has simple technique, easy operation, and low cost, is environment-friendly, and provides graphene quantum dot having high purity, high yield, excellent dispersibility and stability and high fluorescence strength. DETAILED DESCRIPTION - Preparation of graphene quantum dot using 3D graphene as raw material comprises cutting 50x 50 mm2 foamed nickel substrate, ultrasonically cleaning for 30 minutes with absolute ethyl alcohol and deionized water to remove oil stain in surface, placing the foamed nickel in a vacuum tubular furnace, constant temperature heating at 1000 degrees C in 500 standard cm3/minute (sccm) argon atmosphere and in 200 sccm hydrogen atmosphere, keeping the gas flow rate and temperature constant for 10 minutes, sending methane gas for 10 minutes to remove oxide layer of foamed nickel surface, stopping inletting methane, cooling to room temperature at 100-200 degrees C/minute, closing all gas to obtain 3D graphite/foamed nickel composite material, immersing in 4 M nitric acid solution for 2 hours, washing with deionized water, taking out, obtaining 3D graphene, dispersing in alcohol solvent to prepare dispersion liquid having 3D graphene concentration of 10-30 mg/L, adding 100-500 mg/L sodium hydroxide, ultrasonically mixing to obtain mixed liquid, uniformly transferring to a reaction kettle, sealing, placing in 100-200 degrees C oven, reacting for 6-24 hours, cooling to room temperature, vacuum pumping and filtering, collecting to obtain pale yellow filtrate, dialyzing using dialysis bag having molecular weight cutoff of 8000-14000 Da to remove excess alkali ions, obtaining graphene quantum dot dispersion, and drying to obtain solid graphene quantum dot.