The large scale exploitation of fuel cells as clean and sustainable
energy systems is hampered by their high cost which is mostly
contributed by the expensive platinum based electrocatalysts
used. There is therefore high need for electrode materials which
are earth abundant, inexpensive and highly active for the oxygen
reduction reaction (ORR) [1–4]. To this end, a variety of nonplatinum
based electrocatalysts for the ORR have been developed
including among others, M-Nx/C type catalysts [5–8], metal-free
heteroatom doped carbon catalysts [6,9–11], transition metal
chalcogenides [12,13]] and transition metals coordinated to
nitrogen rich polymers [14]. However, although tremendous
progress has been made, the performance of non-precious metal
catalysts generally still trails that of platinum based catalysts