A key step in a fuel cell is the dissociation of hydrogen gas to provide protons and electrons by a catalyst. For low temperature fuel cells carbon black supported platinum-based catalysts are the most promising electrocatalytic materials. A major difficulty with characterising hydrogen is that it potentially occupies many different sites on a catalyst. We have previously successfully exploited the large detector coverage of MAPS at low Q coupled with a large sample to observe the on-top site for the first time on a real Pt/C fuel cell catalyst. However, we were unable to detect the same mode on PtRu/C. The catalytic activity is believed to depend on the particular crystal face that is exposed. In this proposal we aim to study the effect of catalyst morphology on the spectra and to further investigate the differences between the Pt/C and PtRu/C catalyst