▎ 摘　　要

NOVELTY - Preparation of nitrogenous graphene quantum dot composite particles comprises calcining polyacrylonitrile (PAN)-based carbon fibers under argon protection, cooling, and removing sizing agent; dispersing treated PAN-based carbon fibers in concentrated nitric acid, ultrasonically processing, refluxing, cooling, recovering concentrated nitric acid, adjusting pH to neutral with water and ammonia, centrifuging, and dialyzing to obtain yellow fluorescent nitrogen-containing graphene quantum dots; and hydrothermally reacting fluorescent quantum dots and ammonia aqueous solution. USE - Method for preparing nitrogenous graphene quantum dot composite particles (claimed) used in electronics, catalysis and biological imaging fields. ADVANTAGE - The method is simple, easy to operate and suitable for large-scale production. Raw materials have wide source. The composite particles project light between yellow and blue range, and have good water solubility and uniform and stable property. The surfaces of flaky graphene quantum dots are loaded with spherical graphene quantum dots. DETAILED DESCRIPTION - Preparation of nitrogenous graphene quantum dot composite particles comprises: (A) calcining PAN-based carbon fibers under argon protection at 350-500 degrees C for 0.5-2 hours, cooling to room temperature, and removing sizing agent; (B) dispersing 1-2 g pretreated PAN-based carbon fibers in 100-200 ml 65-68% concentrated nitric acid, ultrasonically processing for 1-5 hours, refluxing at 100-150 degrees C for 24-72 hours, cooling to room temperature, recovering concentrated nitric acid by vacuum distillation, adding obtained product to 30-100 ml water and 1-10 ml ammonia to adjust pH to neutral, centrifuging at 5000-9000 revolutions/minute for 10-30 minutes, and dialyzing through membrane with molecular weight cutoff of 1000-10000 Da to obtain yellow fluorescent nitrogen-containing graphene quantum dots with average particle size of 35 nm; and (C) adding 5-100 mg fluorescent quantum dots and 0.05-1.5 ml 28 wt.% ammonia aqueous solution to 20-100 ml water, and hydrothermally reacting at 150-220 degrees C for 2-24 hours.