Applied Catalysis B: Environmental, Vol.142, 15-24, 2013
Oxide-supported PtCo alloy catalyst for intermediate temperature polymer electrolyte fuel cells
A Pt-Co alloy catalyst supported on a Ta-doped Ti-oxide was investigated for the oxygen reduction reaction in a polymer electrolyte fuel cell (PEMFC) operating between 80 and 110 degrees C at different relative humidity (100% and 33% R.H.). A crystalline anatase phase was obtained for the Ta-doped Ti-oxide support with BET surface area of about 150 m(2)/g. Pt and Pt3Co1 nanoparticles dispersed on the Ta-doped Ti-oxide showed a crystallite size of 3.9 and 2.9 nm, respectively. These catalysts were investigated in PEMFC and benchmarked against a carbon supported Pt3Co1 of similar crystallite size (Pt3Co1/C). Under automotive relevant operating conditions, i.e. at intermediate temperatures (110 degrees C), and in the presence of low relative humidity (33% R.H.), the oxide-supported PtCo was approaching in performance the Pt3Co1/C catalyst. The performance of PtCo/oxide was better than that of Pt/oxide under all operating conditions. The oxide supported PtCo catalyst showed a lower electrochemically active surface area (ECSA) and larger ohmic resistance with respect to the Pt3Co1/C. On the other hand, the oxide-supported catalysts appeared stable during an accelerated corrosion test at 1.4 V RHE while a dramatic decrease of the ECSA was observed for the Pt3Co1/C under the same condition. Thus, the oxide supported PtCo alloy catalyst appears promising in terms of electrochemical stability and for automotive applications. (c) 2013 Elsevier B.V. All rights reserved.
Keywords:Pt catalysts;Fuel cells;Oxygen reduction reaction;Doped Ti-oxide support;Intermediate temperature