Oxygen Reduction Reaction on Platinum/Tantalum Oxide Electrocatalysts for PEM Fuel Cells

We investigate platinum supported on tantalum oxide as a possible catalyst for oxygen reduction reaction (ORR) in proton exchange membrane (PEM) fuel cells. Three synthetic routes are evaluated to compare activities of tantalum-oxide-supported platinum fuel cell electrocatalysts: ( i ) deposition of platinum colloids on tantalum oxide followed by mechanical grinding with Vulcan carbon (VC); ( ii ) deposition of tantalum oxide on VC, followed by the deposition of platinum colloids; and ( iii ) deposition of Pt colloids on VC, followed by deposition of tantalum oxide. These are compared to a standard made with the same Pt colloids. The area-specific activities for the ORR at are a factor of 1.5 higher for catalysts synthesized via preparation route ( ii ) compared to a standard. The area-specific activities of the catalysts synthesized via routes ( i ) and ( iii ) are close to that of . The higher area-specific activity of the catalyst synthesized by route ( ii ) may be due to the preferential adsorption of OH groups to the oxide vs platinum surface.