Pt-Co electrodeposited electrodes: surface distribution and depth profile

Electrodeposition is used for the preparation of Pt-Co electrodes for proton exchange membrane fuel cells. Lateral and in-depth inhomogeneities in the composition of the electrodes are followed with different techniques. Cross sectional analysis shows a profile of catalyst concentration decreasing towards the interior of the carbon black substrates. Sputtering assisted XPS analysis shows that the top surface has higher proportion in Pt, increasing the amount of alloyed Co in layers below. Lateral inhomogeneities in composition can be checked on 4x4 cm(2) electrodes with X-ray fluorescence mapping. The electrodes have been tested as cathode in single cell, showing enhanced mass specific activities when compared with standard electrodes.