▎ 摘　　要

NOVELTY - 1-500 g Carbon nitride is placed at one end of sealed quartz tube. Open end is set with cylindrical quartz plugs having outer diameter of 4-99 mm and length of 5 cm. Quartz tube is placed in tube furnace. Protective gas is fed to tube furnace. Quartz tube is heated in tubular furnace at 740-750 degrees C and rate of 1-5 degrees C/minute for 5-120 minutes, to obtain nitrogen-doped graphene. The nitrogen-doped graphene is heated in tube furnace at 800-1000 degrees C and rate of 5-20 degrees C/minute for 30-120 minutes, to obtain nitrogen-doped graphene with adjustable nitrogen doping rate. USE - Preparation of nitrogen-doped graphene used as catalyst for oxygen reduction, photocatalytic reaction and catalytic oxidation, and battery, gas sensor and drug delivery applications. ADVANTAGE - The method enables preparation of nitrogen-doped graphene by simple and environmentally-friendly method. DETAILED DESCRIPTION - 1-500 g Carbon nitride is placed at one end of sealed quartz tube. The quartz tube has inner diameter of 5-100 mm and length of 20 cm. Open end is set with cylindrical quartz plugs having outer diameter of 4-99 mm and length of 5 cm. The difference of inner diameter and outer diameter of quartz tube and quartz plug is 1 mm. Quartz tube is placed in tube furnace, and evacuated to degree of vacuum of (8-9)x 10-4 Pa. Protective gas is fed to tube furnace at flow rate of 50-90 sccm. Quartz tube is heated in tubular furnace at 740-750 degrees C and rate of 1-5 degrees C/minute for 5-120 minutes, to obtain nitrogen-doped graphene. The nitrogen-doped graphene is heated in tube furnace at 800-1000 degrees C and rate of 5-20 degrees C/minute for 30-120 minutes, to obtain nitrogen-doped graphene with adjustable nitrogen doping rate.