200 100

0 200 400 800 800 1000

Current Density (mA/cirf)

Figure 5. Polarization of Pt-RuPc/VuIcan Catalyst in PEMFC Before and After 200 hr LifeTest

Conclusions

Metal phthalocycanine complexes have been evaluated as alternate catalysts for Pt in Hj/02 PEM fuel cells. Preliminary results with (Pt-RuPc)„ and (CoPc)n show very promising catalytic activity for H2 oxidation. PEM fuel cells with unoptimized MEAs using these catalysts performed as well as MEAs containing Pt catalyst. The noble metal loading of the alternate catalysts evaluated in these studies is significantly lower than the precious metal catalyst loading presently being used in fuel cells. During 800 hours of continuous operation at 500 mA/cm2 and 80°C, the fuel cell performance was stable. This vividly demonstrates the stability of the metal macrocyclic complex in the operating environment of the fuel cell. The tolerance of the (Pt-RuPc)„ macrocyclic complex to the presence of CO is superior to the Pt catalyst, in spite of the fact that it contains 0.035 mg Pt/cm2, compared to

0.14.mg Pt/cm2 in the LANL work. Finally, long-term stability tests of PEM fuel cells with (Pt-RuPc)„ catalyst and its tolerance to CO is in progress and the results will be reported in future publications.

References

1. Y. Kiras, J. Electrochem. Soc., 143,2152, (1996) and references therein.

2. S. Mukerjee and J. McBreen, ibid, 143,2285, (1996) and references therein.

3. M.K. Ravikumar and A.K. Shukla, ibid, 143,2601, (1996) and references therein.

4. G. Lalande, G. Tamizhanani, R. Cote, L. Dignard-Bailey, M.L. Trudeau, R. Schulz, D. Guay, and J.P. Dodelet, ibid, 142, 1162, (1995).

6. N. Doddapaneni,ProceedingsoftheSymposiumonLithiumBatteries,PV84-l,p 122,A.N. Dey editor, Electrochemical Society Inc., Pennington, NJ, (1984).

7. M.S. Wilson, C.R. Delouin, J.A. Valerio and S. Gottesfeld, 28th Proceedings Intersociety Energy Conversion Engineering Conf., 1, 1203, (1995).

Acknowledgements

We thank Dr. J. Kosek and Ms. C. Cropley of Giner, Inc for the PEMFC evaluations.

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