Improving design and/or reducing noble metal content in electrocatalysts for fuel cell electrodes while maintaining and/or increasing proton exchange membrane fuel cell (PEMFC) performance in terms of durability and power density are crucial challenges for PEMFC mass market applications.

The formation of platinum alloys with transition metals represents a promising way for improving the activity of Pt-based catalysts [1-3]. Pt based alloys have indeed often demonstrated higher electrocatalytic activity towards ORR than pure platinum.

On the other hand, the structure and morphology of the catalyst [4] also play very important roles in the electrocatalytic efficiency for ORR.

In this context, the present study aims at systematically comparing the catalytic activity and the selectivity towards the ORR of binary and ternary catalysts based on Pt, and Au in order to determine the effects of alloyed metals, in terms of kinetics and selectivity. For this purpose, monometallic Pt/C, binary Pt_xM_1-x/C and ternary Pt_xAu_yM_z/C (with M a transition metal) nanocatalysts supported on carbon have been first synthesized by a wet chemical method allowing the synthesis of the whole range of alloys and comprehensively characterized. The morphologies, compositions and structures of the particles were characterized by physical methods (thermogravimetric analysis, transmission electron microscopy, X-ray diffraction, atomic absorption, X-ray photoelectron spectroscopy). Electrochemical active surface areas and surface compositions were estimated by cyclic voltammetry. Electrocatalytic activity and selectivity of catalysts were studied by rotating disc and rotating ring disc electrodes.

Acknowledgement:

The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) for the Fuel Cells and Hydrogen Joint Technology Initiative under grant agreement #325327 (SMARTCat project) and from the ADEME (French Environment and Energy Management Agency) for its financial support through the EXALAME project.

[1] M.T. Paffet, J.G. Beery, S. Gottesfeld, J. Electrochem. Soc. 135 (1988) 1431–1436.

[2] C. Wang, M. Chi, D. Li, D. van der Vliet, G. Wang, Q. Lin, J. F. Mitchell, K. L. More, N. M. Markovic, V. R. Stamenkovic, ACS Catal. 1 (2011) 1355–1359.

[3] T. Toda, H. Igarashi, H. Uchida, M. Watanabe, J. Electrochem. Soc. 146 (1999) 3750–3756.

[4] D. Alloyeau, C. Mottet, C. Ricolleau, Nanoalloys, London: Springer-Verlag; 2012.