The invention relates to a preparation method for a carbon
fiber material with a composite nano structure. The preparation method comprises the following steps of: pretreating carbon
fiber cloth, adhering a layer of thin iron film catalyst on the carbon
fiber cloth by a liquid-
phase method or a physical deposition method, in a chemical gas-
phase reaction chamber, carrying out in-situ growth of carbon nanotubes on the carbon fiber cloth by using
argon or
nitrogen as a carrier gas,
ethylene or
acetylene gas as a
carbon source gas, and
hydrogen as a reducing gas, then carrying a gas containing
titanium organism into the chemical gas-phase deposition
reaction chamber through the carrier gas, growing
titanium dioxide at the peripheries of the carbon nanotubes to form
titanium dioxide nanoshells which wrap the carbon nanotubes, thus obtaining the carbon fiber material with the composite nano structure. The carbon fiber material obtained by the preparation method has the advantages of high
mechanical strength, high
thermal stability, good chemical inertness and high adsorption property, supernormal strength of carbon nanotubes, large length-
diameter ratio, high
thermal conductivity, good catalytic activity, high
chemical stability, non-
toxicity and super-hydrophilicity. The carbon fiber material with the composite nano structure can have important applications in
photocatalysis, electrocatalysis and other aspects.