In Situ Self-Template Synthesis of Fe–N-Doped Double-Shelled Hollow Carbon Microspheres for Oxygen Reduction Reaction

Herein, we reported a special Fe–N-doped double-shelled hollow carbon microsphere (Fe–N-DSC) which was prepared by a facile, in situ polymerization followed by pyrolysis. With porous ferroferric oxide (Fe3O4) hollow microspheres as the templates, where pyrrole monomers were dispersed around the outer surface and prefilled the interior space. By adding hydrochloric acid, Fe3+ ions were released to initiate polymerization of pyrrole on both the...