2017 Volume 28 Issue 1_2 Pages 11-18
In this study, the ammonia oxidation activity of Pt Black and Pt Oxide Black was investigated by using rotating disk electrode in order to clarify the influence of electrochemical reduction and the content of anion-exchange resin in the electrocatalyst layer. The H2/O2 and NH3/O2 fuel cells were then manufactured by using three types of anode catalysts, namely, Pt Black, Pt Oxide Black and Pt Oxide Black electrochemically reduced, and these discharge performances were examined. The ammonia oxidation activity of the Pt Oxide Black was increased by electrochemical reduction. The activity was also improved by changing the mass ratio of Pt/anion-exchange resin in the electrocatalyst layer. The increase of three-phase boundary was interpreted as the key factor in the improvement of ammonia oxidation activity. Both the H2/O2 and NH3/O2 fuel cells using the Pt Oxide Black electrochemically reduced as the anode catalyst showed the superior discharge performance compared with the fuel cells using the Pt Black or the Pt Oxide Black without reduction. The reaction mechanism of the ammonia oxidation on the former catalyst may be different from those on the two latter catalysts, with the result that the poisoning by the intermediate products of ammonia oxidation on the Pt Oxide Black electrochemically reduced was inhibited.
