ORR Activity of Nb Oxide Based Catalyst Prepared from Nb Compound Including C and N

The development of a non-precious metal cathode catalyst is strongly required for Polymer Electrolyte Fuel Cells (PEFCs) because the cost of platinum and precious metal catalyst is very high. In our previous study, we have reported that oxide-based compounds prepared from group 4 and 5 metal carbonitrides had a high oxygen reduction activity. In this paper, the ORR activity of Nb oxide-based catalysts prepared by heat treatment of the Nb carbide, Nb nitride and Nb carbonitiride under low oxygen pressure was evaluated. Among this, the specimen prepared from Nb carbonitride had a highest ORR activity. We found amorphous carbon on the surface high active catalysts by raman spectroscopy and elemental analysis. Carbon on the surface might affect the ORR activity.