Chitturi, Cabrera and Ishikawa solved the puzzle of the active sites in N-doped nanomaterials for oxygen reduction reaction

09/04/ 2010

Nitrogen-doped carbon nanomaterials are known to exhibit good electrocatalytic activity for oxygen reduction reaction (ORR). However, the structure of ORR-active site and optimum content of nitrogen in carbon lattice for ORR activity remains unknown and has been a challenging question. Better understanding of the active site in these NPCs may lead to the development of materials that could completely eliminate the need for platinum in the energy conversion devices.

Chitturi Venkateswara Rao, Carlos R. Cabrera, and Yasuyuki Ishikawa prepared a series of vertically aligned CNTs (VA-CNTs) having different surface nitrogen concentration by alumina template technique and investigated their electrocatalytic ORR activity. Among them, VA-CNTs with nitrogen concentration of 8.4 atom % exhibited best ORR performance. This is ascribed to a greater number of pyridinic-type nitrogen sites. The good performance of less expensive and virtually metal-free nitrogen-doped CNTs makes the ORR electrodes as a viable alternative to platinum for energy conversion device applications.

These results were just published in J. Phys. Chem. Lett.. This paper is for the first time providing the hard evidence that the active site in the N-doped carbon nanotube electrodes for the oxygen reduction reaction is the pyridinic-type nitrogen site, and is closing the debate on the actual composition and structure of ORR active sites for N-doped carbon nanomaterials for oxygen reduction reaction.

For details, please refer to

In Search of the Active Site in Nitrogen-Doped Carbon Nanotube Electrodes for the Oxygen Reduction Reaction

Chitturi Venkateswara Rao, Carlos R. Cabrera, and Yasuyuki Ishikawa, J. Phys. Chem. Lett. 2010, 1, 2622 – 2627.