Nitrogen and Iron-Codoped Carbon Hollow Nanotubules as High-Performance Catalysts toward Oxygen Reduction Reaction: A Combined Experimental and Theoretical Study

Abstract

Heteroatom-doped carbons represent a unique class of low-cost, effective catalysts for the electroreduction of oxygen, with a performance that may rival that of commercial Pt/C catalysts. In the present study, Fe and N codoped porous carbon nanotubules were prepared by controlled pyrolysis of tellurium nanowire-supported melamine formaldehyde polymer core–sheath nanofibers at elevated temperatures. Electron microscopic studies showed the formation of hollow carbon nanotubules with the outer diameter of 35–40 nm, inner diameter of 5–10 nm, and length of several hundred nanometers. Elemental mapping and spectroscopic measurements confirmed the doping of the carbon nanotubules with N and Fe including the formation of FeN4 moieties. Electrochemical studies showed that the resulting Fe,N-codoped carbons exhibited much enhanced electrocatalytic activity toward oxygen reduction in alkaline media as compared to the counterparts doped with nitrogen alone and prepared in a similar fashion, and the one prepared at 8...