Catalytic Activity of Pt1-xNix (0 < x < 0.8) Measured on High Surface Area NSTF-coated GC disks

Intermixed Pt1-xNix (0 < x < 0.8) and Pt were sputter-deposited onto NSTF-coated GC disks and studied for oxygen reduction reaction (ORR) activity by rotating disk electrode (RDE). It has been established previously that the use of NSTF-coated GC disks in RDE experiments is a viable alternative to the regular mirror-polished GC disks in screening catalyst activities because both the catalytic activities and the effects of high-surface area support can be examined in a single measurement. The sputtered Pt-Ni samples were examined over 80 potential cycles between 0.05 to 1.20 V-RHE in both Ar and O-2-saturated electrolyte to see the impact of potential cycling on the catalyst activity. A selected Pt35Ni65 sample had an SEF of similar to 20 at the beginning which then increased rapidly for the first few cycles before reaching a stable plateau of similar to 3 cm(2)/cm(2) for rest of the CV cycles. The ORR activities of the Pt and Pt-Ni samples, characterized by kinetic current densities, j(planar) and j(specific), extracted at 1.0 V-RHE, showed similar trends. The kinetic current densities of Pt decreased gradually over the course of 80 cycles while the Pt-Ni sample showed a rapid change in the first few cycles before reaching a more subtle decline.