Polymer electrolyte fuel cells (PEFCs) are a green alternative to the internal combustion engine, particularly in the transportation sector. Currently platinum (Pt) is a state-of-the-art catalyst for both anode and cathode. As the oxygen reduction reaction (ORR) is inherently six orders of magnitude slower than the anodic hydrogen oxidation, there is a significantly higher Pt loading requirement for the cathode. Volatile pricing and geopolitical instabilities of the precious-metal market have thus enthused the development of entirely non-platinum group metal (non-PGM) cathode catalysts for PEFCs.

With the recently realized highly active non-PGM catalyst development,^1-5 implementing these catalysts into PEFCs and demonstrating high fuel cell performance (i.e., competitive with state-of-the-art Pt catalysts) is becoming increasingly needed. Up until now, a majority of non-PGM catalysts have been tested under H₂-O₂ conditions, which tend to mask the true effects of mass transport likely encountered under practical automotive applications conditions (H₂-air).

Recently, we introduced a new non-PGM ORR catalysts derived from two nitrogen precursors, cyanamide and polyaniline, both exhibiting high H₂-air fuel cell performances.⁶ To understand the fuel cell performance of these catalysts more deeply under H₂-air condition, we have tested/characterized theses catalysts using diverse H₂-air fuel cell test conditions and characterization methods: H₂-helox fuel cell testing, impedance characterization, as well as carbon dioxide and fluoride emissions detection. These results promise to provide a better insight into the performance of the dual nitrogen precursor catalysts under the conditions approaching those of an automotive fuel cell power system.

Acknowledgement

Financial support for this research by DOE-EERE through Fuel Cell Technologies Office is gratefully acknowledged. Microscopy research supported through a user project at ORNL’s Center for Nanomaterials Sciences, which is an Office of Science User Facility.

References

1. K. Strickland, M. W. Elise, Q. Y. Jia, U. Tylus, N. Ramaswamy, W. T. Liang, M. T. Sougrati, F. Jaouen, and S. Mukerjee, Nat. Commun, 6:73433; DOI: 10.1038 (2015).
2. J. L. Shui, C. Chen, L. Grabstanowicz, D. Zhao, and D. J. Liu, Proc. Natl. Acad. Sci. U.S.A. 112, 10629 (2015).
3. A. Serov, K. Artyushkova and P. Atanassov, Adv. Energy Mater., 4, 1301735 (2014).
4. E. Proietti, F. Jaouen, M. Lefèvre, N. Larouche, J. Tian, J. Herranz and J.-P. Dodelet, Nat. Commun, 2, 415 (2011).
5. G. Wu, K. L. More, C. M. Johnston and P. Zelenay, Science, 332, 443 (2011).
6. H. Chung, D. Higgins, D-H. Kim, G. Wu, U. Tylus, K. L. More, D. Cullen, P. Zelenay, 227^th ECS Meeting, Chicago, IL, USA (2015).