Activity of Tantalum Oxide-Based Electrocatalysts toward Oxygen Reduction Reaction for PEFC

Abstract

Development of non-noble metal cathode is required to commercialize polymer electrolyte fuel cells. We have investigated group 4 and 5 transition metal oxide-based cathode. In this paper, tantalum oxide-based cathodes with nano-sized particles were made from oxy-tantalum phthalocyanines (TaOPc) as starting material by heat treatment under low oxygen partial pressure. The kind of catalyst supports, the oxidation temperature, and ball milling were examined to increase the oxygen reduction current. It was found that multi-walled carbon nanotube (MWCNT) was effective as catalyst support. In addition, the oxidation at 900 o C under low oxygen partial pressure and ball milling were also effective to enhance the oxygen reduction activity. The maximum i ORR current density at 0.8 V vs. RHE was about 106 mA g -1 .