▎ 摘　　要

NOVELTY - A composite visible photocatalyst graphene quantum dot/graphite phase nitrogen carbide is prepared by pyrolyzing citric acid monohydrate at 200 plus minus 5 degrees C for 30-35 minutes, cooling product, adding sodium hydroxide solution to adjust pH to 7, storing liquid at 4 degrees C, naming as graphene quantum dot solution, calcining melamine at 500-550 degrees C for 4-6 hours, cooling solid to room temperature, grinding into powder, naming as carbon nitride, mixing 0.2-0.6 g carbon nitride and 1-15 ml graphene quantum dot solution, stirring at room temperature for 30-60 minutes, pouring mixed solution into PTFE reaction kettle, reacting to 180 plus minus 5 degrees C for 4 plus minus 0.1 hours, cooling product to room temperature, centrifuging to remove supernatant, respectively washing using deionized water and absolute ethanol, and drying to obtain solid. USE - The method is used for preparing composite visible photocatalyst graphene quantum dot/graphite phase nitrogen carbide. ADVANTAGE - The method solves problem of low efficiency of degrading nitric oxide under visible light of graphitic carbon nitride, improves ability of graphene quantum dot/carbon nitride to degrade nitric oxide, and enhances selectivity of nitrate ion generation.