Pt-alloy electrocatalysts have been investigated for operation in both hydrogen and methanol-fed polymer electrolyte membrane (PEM) fuel cells with the aim of evaluating their performance and resistance to degradation. Nanosized PtCo catalysts with particle size of about 3 nm were prepared by using a sulphite complex route [1-4]. To achieve a high degree of alloying a carbothermal reduction was used. This caused the occurrence of a primitive cubic ordered structure. The surface properties were investigated by X-ray photoelectron spectroscopy (XPS) and low-energy ion scattering spectroscopy (LE-ISS, 3He+ at 1kV). The formation of a Pt skin layer on the surface of the alloy electro-catalyst was studied. Oxide supports were evaluated as alternative to carbon black materials with the aim to increase the electrochemical stability. The structural and surface characteristics of the samples as well as the type of catalyst support appear to strongly influence the PtCo catalyst performance and degradation. References [1] Aricò, A.S., Stassi, A., Modica, E., Ornelas, R., Gatto, I., Passalacqua, E., Antonucci, V. Performance and degradation of high temperature polymer electrolyte fuel cell catalysts Journal of Power Sources, (2008) 178 (2), pp. 525-536. [2] Aricò, A.S., Stassi, A., Gatto, I., Monforte, Passalacqua, E., Antonucci, V. Surface Properties of Pt and PtCo Electrocatalysts and Their Influence on the Performance and Degradation of High-Temperature Polymer Electrolyte Fuel Cells, J. Phys. Chem. C (2010), 114, 15823–15836. [3] Baglio, V., D'Urso, C., Sebastián, D., Stassi, A., Aricò, A.S. PtCo catalyst with modulated surface characteristics for the cathode of direct methanol fuel cells (2014) International Journal of Hydrogen Energy, 39 (10), pp. 5399-5405. [4] Stassi, A., Gatto, I., Baglio, V., Passalacqua, E., Aricò, A.S. Oxide-supported PtCo alloy catalyst for intermediate temperature polymer electrolyte fuel cells (2013) Applied Catalysis B: Environmental, 142-143, pp. 15-24. Acknowledgement The research leading to these results has received funding from the European Community’s Seventh Framework Programme (FP7/2011-2014) for the Fuel Cells and Hydrogen Joint Technology Initiative under grant agreement Impact n° 303452.