Mesoporous carbon nanofibers with large cage-like pores activated by tin dioxide and their use in supercapacitor and catalyst support

The mesoporous carbon nanofibers (MCFs) with large cage-like pores have been fabricated by thermally treating electrospun fibers of polyvinyl alcohol containing tin compound. During the process, tin oxide is reduced to melting tin and the carbon is activated to form the porous carbon. The results of X-ray diffraction and transmission electron microscopy at different temperatures show that particles of SnO2 (∼1.9 nm) exist in the fibers at 300 °C while mixtures of Sn and SnO with rod-like shapes appear in the matrix when the fibers are heated at 400 °C, and that Sn migrates to the surface of fibers and pores are formed in the fibers at higher temperature. Specific surface area of MCFs can reach 800 m2 g−1 and the average diameter of interior pores is about 10.3 nm while the entrance pores are small. The specific capacitance of MCFs is 105 F g−1 and the fabricated symmetrical capacitors exhibit high-rate capacitive properties and excellent stability, Pt nanoparticles which can be densely loaded on MCFs exhibit relatively high activity and stability toward electro-oxidation of methanol, which indicate that MCFs may be used as electrodes for high-rate energy storage and support for catalyst. This approach may be extended to prepare other porous carbon materials.