▎ 摘　　要

NOVELTY - Preparing composite catalyst involves adding 50-100ml ethylene glycol, 10-15ml tetrabutyl titanate, 0.1-0.5g polyamine and 0.05-2g citric acid into a 250ml three-necked flask, stirring at room temperature for 1-2h, refluxing the stirred solution in an oil bath at 150-200°C for 36-48h. After the reactant is cooled to room temperature, it is centrifuged, washed three times with absolute ethanol and deionized water respectively, and dried in an oven at 50-100°C for 6-12h to obtain nitrogen doped graphene quantum dots-titanium oxide composite photocatalyst. USE - Method for preparing composite catalyst used for efficiently utilizing visible light and near-infrared light. ADVANTAGE - The method uses one-pot method, utilizes a high-boiling-point water-absorbing solvent to control the hydrolysis rate of butyl titanate, and then titanium cation forms a stable complex with polyamines, and then the polyamine edge N reacts with citric acid to form N-doped graphene carbon quantum dots, which increases the amount of N doping and stably doped into the titanium dioxide grains. The coordination between the lone electron pair and titanium cation loads N-doped graphene carbon quantum dots on the surface of titanium dioxide in situ. On the one hand, it realizes the doping of organic N, and on the other hand, it disturbs the crystal lattice of titanium dioxide, so as to realize the utilization of the titanium dioxide main body for the long wave light.