BCN Graphene as Efficient Metal-Free Electrocatalyst for the Oxygen Reduction Reaction

The cathodic oxygen reduction reaction ORR is an important process in fuel cells and metal air batteries.1 3 Although Pt-based electrocatalysts have been commonly used in commercial fuel cells owing to their relatively low overpotential and high current density, they still suffer from serious intermediate tolerance, anode crossover, sluggish kinetics, and poor stability in an electrochemical environment. This, together with the high cost of Pt and its limited nature reserves, has prompted the extensive search for alternative low-cost and high-performance ORR electrocatalysts. In this context, carbon-based metal-free ORR electrocatalysts have generated a great deal of interest owing to their low-cost, high electrocatalytic activity and selectivity, and excellent durability.4 9 Of particular interest, we have previously prepared vertically aligned nitrogendoped carbon nanotubes VA-NCNTs as ORR electrocatalysts, which are free from anode crossover and CO poisoning and show a threefold higher catalytic activity and better durability than the commercial PtC catalyst.4