Five percent platinum-tungsten oxide-based electrocatalysts for phosphoric acid fuel cell cathodes

A Pt-tungsten oxide-based electrocatalyst has been fabricated by an inexpensive chemical route for use as an oxygen cathode in 99% phosphoric 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 current density and mass activity of a 5% Pt-40% WO3-based electrode were 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 two electrodes are similar. It was shown that an increase in its electrochemically active surface area was the only reason for the performance of the 5% Pt-40% WO3 based electrode. The electrocatalytic parameters of the 5% Pt-40% WO3-based electrode for the ORR were compared to those of the 2% Pt-1% H2WO4-based electrode.