Preparation method of porous nano carbon fibers

The invention discloses a preparation method of porous PAN (Polyacrylonitrile)-based nano carbon fibers. The preparation method comprises the following steps: weighing PVP (Polyvinyl Pyrrolidone) andPAN respectively; adding DMF (Dimethyl Formamide), heating, stirring and dissolving to obtain PVP and PAN solutions; sucking the PVP and PAN solutions into an injection syringe; then fixing the injection syringe on an electrostatic spinning machine; taking the PAN solution as a surface layer and the PVP solution as a core layer, and carrying out coaxial electrostatic spinning; putting a spun fibermembrane into water and heating; after washing, drying to obtain hollow PAN nano-fibers; pre-oxidizing the hollow PAN nano-fibers; under the protection of nitrogen gas, raising the temperature to 500to 700 DEG C at the temperature rising speed of 1 to 5 DEG C/min and then raising the temperature to 800 to 1000 DEG C at the temperature rising speed of 1 to 10 DEG C/min, and carrying out carbonization; then naturally coolin