In this paper we compare the performance and stability of state of the art carbon based catalysts with non carbon based catalyst. Technically Iridium-Oxide supported Platinum exhibits excellent stability under corrosion at 1.4V, with good transport properties and activity in a fuel cells electrode. However for commercial success there is a need for replacing Iridium. As one potential example we have prepared Antimony doped Tin-Oxide supported Platinum. This material is showing fundamentally promising properties, but instability of the dopant leads to a reduction in activity of the catalyst.

The stability of a series of sulfated zirconia catalysts, promoted with up to 2 wt% iron or manganese, in their calcined state was investigated. Phase composition, nature of surface sulfate species, degree of hydroxylation, and butane isomerization activity changed duri ng aging over months in various atmospheres and during milling. The metastability of small oxide particles is discussed, including literature data on alumina, titania and other oxides. Catalytically active fractions of a material easily transition into more stable, less active forms.