Method for preparing nano-carbon fibers

The invention discloses a method for preparing nano-carbon fibers. The linear and spiral nano-carbon fibers are prepared by catalyzing C2H2 under the catalysis condition. The method comprises the following steps of: (a) dispersing cupric tartrate powder on a ceramic boat substrate carrier in an amount of between 0.5 and 2.5mg/cm ; (b) putting the ceramic boat filled with the cupric tartrate powder in the middle of a quartz tube in a horizontal furnace, controlling the temperature of the heating furnace to between 270 and 390 DEG C, and decomposing the cupric tartrate for 15 to 60 minutes in a decomposing atmosphere to obtain catalyst particles; and (c) controlling the reaction temperature of between 195 and 274 DEG C to in-situ prepare the linear or spiral nano-fibers on the catalyst particles by adopting acetylene gas serving as a reactant. The size and geometric appearance of the catalyst particles are influenced by different decomposition atmospheres of the catalyst precursor, so that the nano-carbon fibers with different appearances can be prepared by catalyzing the acetylene.