Ex Situ and In Situ Stability of Platinum Supported on Niobium-Doped Titania for PEMFCs

The stability and activity of niobium-doped titania were compared to those of commercial catalyst (HiSpec 4000), both ex situ and in a proton exchange membrane fuel cell. The stability test involved holding the cell at for . Fuel cell polarization curves were obtained both before and after the potential holds. Cyclic voltammogram data showed that the Pt surface area was stable for even after holding for at . A significant drop in the Pt surface area was observed, however, for after at . The high potential hold test showed significantly higher stability of the membrane electrode assembly with compared to that with .