▎ 摘　　要

NOVELTY - Preparation of nitrogen-doped graphene silica coaxial nanotube involves mixed grinding solid melamine and mixed powder of silicon and silica as reaction materials for 40 minutes to obtain raw materials; cleaning graphite substrate; drying and soaking in 0.01 mol/l nickel nitrate ethanol solution for 5 minutes; removing and drying to obtain carbon substrate; grinding to obtain graphite substrate impregnated catalyst; putting raw materials and graphite substrate impregnated catalyst in graphite reaction chamber; putting graphite reaction chamber in vacuum furnace; and reacting. USE - Preparation of nitrogen-doped graphene silica coaxial nanotube used as field emission cathode materials (claimed) for flat panel display, vacuum electronic device, large screen liquid crystal display backlight module, or in field emission illumination light source. ADVANTAGE - The method has simple process, has low cost, is easy to control, and has good reproducibility. It produces nitrogen-doped graphene silica coaxial nanotube with diameter of 150-250 nm and has silica coating, thus providing excellent field emission performance. DETAILED DESCRIPTION - Preparation of nitrogen-doped graphene silica coaxial nanotube involves taking solid melamine as raw material and mixed powder of silicon and silica at mass ratio of 1.5:1 as reaction materials; mixed grinding raw materials and reaction materials in agate mortar for 40 minutes to obtain raw material; cleaning graphite substrate in ultrasonic cleaning machine; drying and soaking in 0.01 mol/l nickel nitrate ethanol solution for 5 minutes; removing and drying to obtain carbon substrate; grinding to obtain graphite substrate impregnated catalyst; putting raw material and graphite substrate impregnated catalyst in graphite reaction chamber; putting graphite reaction chamber in vacuum furnace; heating under vacuum atmosphere of 50-80 Pa at 15 degrees C/minute to 1200-1250 degrees C for 20-30 minutes; passing methane gas at 0.10-0.15 sccm for 25-30 minutes; closing vent valve to stop methane; cooling furnace at room temperature; and taking out template to obtain nitrogen-doped graphene silica coaxial nanotube.