▎ 摘　　要

NOVELTY - The method for preparing nitrogen-doped graphene involves (a) fully mixing graphite and concentrated sulfuric acid, (b) heating and adding potassium permanganate, (c) heating, (d) again heating, (e) cooling to room temperature and adding hydrogen peroxide to carry out reaction, (f) purifying to obtain graphene oxide, (g) uniformly mixing graphene oxide with water, nitrogen-containing compound and reducing agent, reacting, uniformly mixing graphene oxide with nitrogen-containing compound and reducing agent, heating, and (h) purifying and drying to obtain nitrogen-doped graphene. USE - Method is useful for preparing nitrogen-doped graphene (claimed). ADVANTAGE - The nitrogen-doped graphene can be prepared with increased yield of 32-42% and less structural defect. DETAILED DESCRIPTION - The method for preparing nitrogen-doped graphene involves (a) fully mixing graphite and concentrated sulfuric acid at -5 degrees C to 5 degrees C, (b) heating at 10-20 degrees C and adding potassium permanganate 3-6 times for 5-15 minutes in each time, (c) heating at 25-60 degrees C and reacting for 1-2 hours to obtain a mixed reaction solution, (d) again heating at 98-100 degrees C for 20-60 minutes, (e) cooling to room temperature and adding hydrogen peroxide to carry out reaction, (f) purifying to obtain graphene oxide, (g) uniformly mixing graphene oxide with water, nitrogen-containing compound and reducing agent, reacting at 50-180 degrees C for 3-8 hours, uniformly mixing graphene oxide with nitrogen-containing compound and reducing agent, heating at 200-400 degrees C for 20-40 minutes, again heating at 400-600 degrees C for 20-40 minutes and finally heating at 700-900 degrees C for 20-40 minutes, and (h) purifying and drying to obtain nitrogen-doped graphene. The mass volume ratio of graphite to concentrated sulfuric acid is 1:15-40 g/ml. The mass ratio of graphite to potassium permanganate is 1:3-6. The mass volume ratio of the graphite to hydrogen peroxide is 1:10-25 g/ml. The nitrogen-containing compound is dimethylformamide, urea or melamine. An INDEPENDENT CLAIM is included for nitrogen-doped graphene prepared by the above method, where nitrogen doping rate of the nitrogen-doped graphene is 6.2-8.1% and fewer structural defects are formed by oxygen atoms intercalating into the carbon layer.