Characterization of Nb and W Doped Titania as Catalyst Supports for Proton Exchange Membrane Fuel Cells

Niobium doped titania and tungsten doped titania prepared using a sol-gel technique were evaluated as possible catalyst support materials for proton exchange membrane fuel cells. The electrical conductivity of the doped materials prepared under different heat-treatment temperatures and partial oxygen pressures was measured Rutile 10Nb-TiO2 was extremely conductive compared to the anatase 10M-TiO2. For the W doped samples the conductivity was found to be extremely low compared to the rutile 10Nb-TiO2, and W segregation was observed when the material was reduced in H-2 at temperatures greater than 700 degrees C. X-ray photoelectron spectroscopy (XPS) analysis was completed on 10Nb-TiO2 calcined at 500 degrees C and on 10Nb-TiO2 calcined and then reduced at a range of temperatures (500 degrees C to 900 degrees C).