Uniform Polyaniline Nanotubes Formation via Frozen Polymerization and Application for Oxygen Reduction Reactions

A frozen polymerization technique to prepare uniform polyaniline (PANI) nanotubes is reported, based on the concept of the Kirkendall effect that has been successfully applied for preparation of inorganic hollow nanostructures. Specifically, PANI nanotubes with a uniform diameter of 45 nm are prepared by combination of freezing and templating to control the diffusion of aniline and ammonium persulfate at the PANI interface. Due to the low entropy diffusion at solid state and polymerization at low temperature, ordered packed anilines and high crystalline PANI nanotubes are obtained, which greatly facilitate the conversion to conductive nanotubes with nanoscale graphitic domains at low carbonization temperature. The resulting conductive nanotubes exhibit improved catalytic performance in oxygen reduction reactions, suggesting the high potential application of the frozen polymerization technique in preparation of high performance PANI nanostructures.