Design of supported PtCo electrocatalysts for pemfcs

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. Nanosized PtCo catalysts with particle size of about 3 nm were prepared by using a sulphite complex route. 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. The structural and surface characteristics of the samples as well as the type of catalyst support appear to strongly influence the PtCo catalyst performance.