A N-doped rice husk-based porous carbon as an electrocatalyst for the oxygen reduction reaction

N-doped rice husk-based porous carbon (N-RHPC) was cost-effectively prepared by simply treating RHPC at high temperature in an ammonia atmosphere. Results show that the mesopore volume and degree of graphitization of N-RHPC are significantly increased by the treatment. N atoms are doped in the RHPC structure in the form of pyridinic N (398.5 +/- 0.1 eV), pyridonic N (399.3 +/- 0.1 eV), and graphitic N groups (401.1 +/- 0.1 eV) and N-oxide (401.8 +/- 0.1 eV). Compared with a commercial Pt/C catalyst, the N-RHPC as an oxygen reduction electrocatalyst has a similar electrocatalytic activity, and better sTableility and methanol toxicity resistance. This excellent performance is ascribed to the increased number of catalytic sites afforded by the nitrogen species, the improved degree of graphitization that increases electron transfer, and the unique pore structure with macropores, mesopores and micropores for fast ion transport.