▎ 摘　　要

NOVELTY - Pyrene and an acid are reflux-reacted, cooled, slowly added to ice water solution, and filtered. The acid solution is removed and the solid is washed several times with distilled water. The obtained solid is ultrasonically dispersed in distilled water and stirred with a mixture of aqueous ammonia and hydrazine hydrate. The pH is set to 12, and the mixture is reacted. After natural cooling, the mixture is filtered using a 25-nm filter, dialyzed, rotary-evaporated, and dried to obtain multicolor fluorescence graphene quantum dot powder. USE - Preparation of multicolor fluorescence graphene quantum dots for use in environmental protection, bio-nanotechnology, energy, and nano-device fields. ADVANTAGE - The method uses economical pyrene and provides quantum dots which can be stably dispersed in water. The quantum dots are brown under low concentration and approximately black under high concentration. Light emitting color or wavelength is adjustable (blue to yellow, 450-535 nm). The method is simple and environmentally-friendly, consumes less energy, and is suitable for industrial scale-up. DETAILED DESCRIPTION - Pyrene and an acid are mixed in a ratio of 1 g:50-80 ml, reflux-reacted for 20-40 hours, and cooled. The reaction product is slowly added to ice water solution, and filtered using a membrane filter. The acid solution is removed and the solid is washed several times with distilled water till the water pH is 7. The obtained solid is ultrasonically dispersed in distilled water for 2 hours and stirred with a mixture of 1 mL 25-28% aqueous ammonia and 5 mL hydrazine hydrate. The pH is set to 12, and the mixture is reacted for 3-24 hours at 180-230 degrees C. After natural cooling, the mixture is filtered using a 25-nm filter, dialyzed, rotary-evaporated, and dried to obtain multicolor fluorescence graphene quantum dot powder. The acid is nitric acid, concentrated sulfuric acid, or mixture nitric acid and concentrated sulfuric acid 1:1-4 v/v.