Cobalt-Containing Nitrogen-Doped Carbon Aerogels as Efficient Electrocatalysts for the Oxygen Reduction Reaction

The electrocatalysis of the oxygen reduction reaction (ORR) on cobalt-containing nitrogen-doped carbon aerogels (CAs) was studied in alkaline solution. CA-based catalyst materials with varied compositions were prepared through the sol-gel polymerisation of organic precursors (resorcinol derivatives and melamine), followed by insertion of Co by using an ion-exchange process and pyrolysis. The concentrations of the precursors had a large effect on the structure and physicochemical properties of the materials, as characterised by using SEM, XRD, XPS, atomic adsorption spectroscopy, and N-2-adsorption analysis. The electrocatalytic activity of Co-containing N-doped CAs for the ORR was higher than that of nitrogen-free CA, and this activity increased with increasing Co content. The most active catalyst materials supported the four-electron reduction of O-2 and short-term stability tests indicated their high durability. Co-containing N-doped CAs can be regarded as a promising class of material for the cathode catalysts of alkaline membrane fuel cells.