▎ 摘　　要

NOVELTY - Preparing nitrogen-doped graphene quantum points comprises e.g. taking pyrene as precursor, nitrifying the surface, carrying out hydrothermal reaction, cutting the hexagonal ring structure of pyrene, adding aqueous ammonia as nitrogen source, uniformly stirring, completely mixing, transferring into polytetrafluoroethylene tank, carrying out hydrothermal reaction, naturally cooling, taking out and filtering the reaction product, and dialyzing to obtain nitrogen-doped graphene quantum point. USE - The quantum point is useful for photocatalytic synthesis of nitrogen-doped graphene quantum dots/phosphorus titanium dioxide (P25TiO2) composite material (claimed). ADVANTAGE - The method: has high yield and less impurities; and is simple. The quantum dots: can be stably dispersed in water; and has structural stability and optical performance. DETAILED DESCRIPTION - Preparing nitrogen-doped graphene quantum points comprises (i) preparing graphite quantum point: taking pyrene as precursor under low temperature condition, controlling proportion of raw materials, processing raw materials, nitrifying the surface of the pyrene, carrying out hydrothermal reaction under high temperature and high pressure to remove the nitrene surface of pyrene, cutting the hexagonal ring structure of pyrene to obtain graphite quantum point, and (ii) preparing nitrogen-doped graphene quantum point: taking graphite quantum point obtained in the (i), and aqueous ammonia as nitrogen source, uniformly stirring, completely mixing, transferring into polytetrafluoroethylene tank, carrying out hydrothermal reaction, naturally cooling, taking out and filtering the reaction product, and dialyzing to obtain nitrogen-doped graphene quantum point. An INDEPENDENT CLAIM is also included for nitrogen-doped graphene quantum point prepared according to the above mentioned method.