5 PERCENT PLATINUM-TUNGSTEN OXIDE-BASED ELECTROCATALYSTS FOR PHOSPHORIC-ACID FUEL-CELL CATHODES

A Pt-tungsten oxide-based electrocatalyst has been fabricated by an in expensive chemical route for use as an oxygen cathode in 99% phosphori c acid at 180 degrees C. The effect of %WO3 (wt/wt) on the Pt-tungsten oxide/C-based electrode performance was studied. The electrocatalytic properties for the oxygen reduction reaction (ORR), e.g., exchange cu rrent density and mass activity of a 5% Pt-40% WO3-based electrode wer e found to be twice as high as those of 10% Pt, which contains double the amount of platinum. The Tafel slope and specific activity of the t wo electrodes are similar. It was shown that an increase in its electr ochemically active surface area was the only reason for the performanc e of the 5% Pt-40% WO3 based electrode. The electrocatalytic parameter s of the 5% Pt-40% WO3-based electrode for the ORR were compared to th ose of the 2% Pt-1% H2WO4-based electrode.