▎ 摘　　要

NOVELTY - Preparing graphene nano-tube comprises (i) adding graphene oxide into solvent, ultrasonically dispersing for 2-3 hours to obtain graphene oxide dispersion, adding solute into the graphene oxide dispersion liquid, and stirring at 65 degrees C under water bath condition for 24 hours, where the mass ratio of the graphene oxide and solute is 1/11 -1/5, and the total mass concentration of the graphene oxide and solute is 10-15%, (ii) introducing nano composite fiber protofilament in electrostatic spinning device using solution, where the electrostatic spinning condition is as follows: the voltage is 25kv, the substrate distance of needle distance is 25 cm, the solution feed rate is 1 ml/hour, and (iii) pre-oxidizing composite nano fiber precursor at 220-240 degrees C for 100-120 minutes, heating to 950-1050 degrees C under the protection of inert atmosphere, introducing ammonia to reacting for 30-60 minutes, closing ammonia gas and introducing inert gas after ending the reaction, cooling the furnace. USE - The nanotubes is useful for preparing an intelligent switch device (claimed). ADVANTAGE - The nanotubes has excellent field emission effect performance.