Cobalt- and iron-containing nitrogen-doped carbon aerogels as non-precious metal catalysts for electrochemical reduction of oxygen

Nitrogen-doped carbon aerogels containing transition metals have been used as non-precious metal catalysts for oxygen reduction reaction (ORR). The electrocatalysts were prepared by sol-gel polymerisation of organic precursors, followed by insertion of Co or Fe by ion exchange and subsequent carbonisation. The resulting materials were characterised by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Electrochemical testing of the catalysts by thin-film rotating disk and ring-disk electrode technique revealed their high activity and stability in alkaline solution. Cobalt-containing aerogel showed slightly better performance than iron-containing material and the aerogel not containing transition metals was considerably less active. The Koutecky-Levich analysis indicated nearly four,electron reduction of 02 on metal-containing nitrogen-doped carbon aerogels. The non-precious metal catalysts studied could be used as cathode materials for alkaline membrane fuel cells. (C) 2015 Elsevier B.V. All rights reserved.