Due to electrical conductivity, specific surface area, pore size distribution and chemical inertness requirements, the replacement of high surface area carbon supports used in proton-exchange membrane fuel cells is challenging. In this context, tin dioxide (SnO2, TO) based materials have already shown promises but their long-term stability in the various potential ranges experienced by a PEMFC cathode remains unexplored. In this study, niobium (Nb)-doped tin oxide (NTO) and antimony (Sb)-doped tin oxide (ATO) aerogels were synthesized, characterized and catalyzed with Pt nanoparticles using a unique colloidal suspension batch. Electrochemical experiments demonstrated that the oxygen reduction reaction (ORR) activity is strongly impacted by the electrical conductivity of the support (the larger the electrical conductivity, the larger the ORR activity). The stability of the best performing electrocatalyst (Pt/ATO) was studied using rotating disk and rotating ring disk electrode, energy dispersive X-ray spectroscopy and inductively-coupled plasma mass spectrometry. The results show that both Sb and Sn atoms are dissolved from ATO and poison the Pt catalytic sites. This process is accelerated during potential excursions at low electrode potential, e.g. during electrochemical characterizations or kinetic measurements.