Catalyst Durability for Fuel Cells under Start-up and Shutdown Conditions: Evaluation of Ru and Ir Sputter-Deposited Films on Platinum in PEM Environment

Electrochemical and surface properties of Ru, Ir and Ti over-layers sputter-deposited onto 3M Pt-coated nano-structured thin film (NSTF) substrate were evaluated in PEM environment. Ti was included because it is often combined with Ru and Ir to improve stability of these highly active catalysts for oxygen evolution reaction (OER). Different OER catalyst coating thicknesses were formed by varying Ru, Ir and Ti mass in the range of 1-10 mu g/cm(2) Pt-NSTF geometric area. The OER activity was assessed by quasi-steady state polarization measurements. The electrochemical data demonstrate that the OER catalytic activity of Ru and Ir in PEM compares well with their behavior in aqueous environment. The OER catalysts composition on Pt-NSTF was characterized by XPS. The XPS results indicate the organo-metallic bonds formation at the interface of Ru OER catalysts with Pt-NSTF.