Dissolution of Ni from High Ni Content Pt1−xNix Alloys

Abstract

Three Pt 1Àx Ni x catalyst compositions, with high Ni content, were sputter deposited onto 3M Company's Nano-Structured Thin Film catalyst support to determine whether the high oxygen reduction reaction (ORR) activities recently reported are a surface phenomenon or require bulk Ni dissolution. The electrodes with Pt 0.27 Ni 0.73 throughout had the highest mass specific ORR activity of the samples tested. When some of the Pt 0.27 Ni 0.73 was replaced with either Pt or Pt 0.75 Ni 0.25 , the mass activity dropped. These results confirmed that continuous high Ni content is required to obtain high mass activity. Platinum-transition metal alloy catalysts such as Pt-Co, Pt-Cu, Pt-Ni etc. have been shown to exhibit higher oxygen reduction reac-tion (ORR) activity than platinum for Proton Exchange Membrane Fuel Cells. 1 Recent results for Pt 1Àx Ni x sputter deposited on 3M Company's Nano-Structured Thin Film (NSTF) catalyst support 2,3