▎ 摘　　要

NOVELTY - Template-free one-step method for preparing graphite-type nitrogen-doped graphene tube in high proportion, involves mixing solid melamine and silicon powder, immersing graphite substrate in nickel nitrate/ethanol solution, placing carbon cloth, mixed raw material and graphite substrate into a graphite reaction chamber, evacuating vacuum atmosphere furnace to a vacuum degree of 50-80 Pa, introducing methane gas, closing the valve gates, stopping the introduction of methane gas and cooling the furnace to room temperature to obtain graphite-type nitrogen-doped graphene tube. USE - Template-free one-step method for preparing graphite-type nitrogen-doped graphene tube in high proportion, used in vacuum microelectronic devices, nano-optoelectronic devices and nano-super capacitors. ADVANTAGE - The destruction of the tube structure during the process of removing the template is avoided. The preparation process is simple and easy to control. The nitrogen-doped graphene tube is featured with high purity, uniform structure, and good repeatability. The nitrogen configuration can effectively improve the electrical performance of the product. DETAILED DESCRIPTION - Template-free one-step method for preparing graphite-type nitrogen-doped graphene tube in high proportion, involves mixing solid melamine and silicon powder and grinding in an agate mortar for 40 minutes, washing the graphite substrate in an ultrasonic cleaning machine, immersing in 0.01 mol/L nickel nitrate/ethanol solution for 5 minutes after drying, naturally drying the substrate, placing carbon cloth, mixed raw material and graphite substrate into a graphite reaction chamber arranged in the vacuum atmosphere furnace, evacuating the vacuum atmosphere furnace to a vacuum degree of 50-80 Pa at 15 degrees c/minute, increasing the furnace temperature to 1200-1250 degrees C and maintaining for 20-30 minutes, introducing 0.10-0.15 sccm methane gas at the aeration rate for 5-10 minutes, closing the valve gates, stopping the introduction of methane gas, turning-off the power, and cooling the furnace to room temperature to obtain graphite-type nitrogen-doped graphene tube.