Carbon supported Pt-Y electrocatalysts for the oxygen reduction reaction

Carbon supported Pt-3 y(Pt-3 Y/C) were investigated as oxygen reduction reaction (ORR) catalysts. After synthesis via reduction by NaBH4, the alloy catalysts exhibited 10-20% higher mass activity (mAmg(Pt)(-1)) than comparably synthesized Pt/C catalyst. The specific activity (mu A cm(Pt)(-2)) was 23 and 65% higher for the Pt-3 Y/C and PtY/C catalysts, respectively, compared to Pt/C. After annealing at 900 degrees C under a reducing atmosphere. Pt3Y/C-900 and PtY/C-900 catalysts showed improved ORR activity; the Pt/C and PtY/C-900(Pt/C catalyst annealed at 900 degrees C) catalysts exhibited specific activities of 334 and 393 mu A cm(Pt)(-2), respectively, while those of Pt-3 Y/C-900 and PtY/C-900 catalysts were 492 and 1050 mu A cm(Pt)(-2), respectively. X-ray diffreaction results revealed that both the Pt-3 Y/C and PtY/C catalysts have a fcc Pt structure with slight Y doping. After annealing. XRD showed that more Y was incorporated into the Pt structure in the Pt-3 Y/C-900 catalyst, while the PtY/C-900 catalyst remained unchanged. Although the results suggested that the high ORR acitivity of the PtY/C-900 catalyst did not originate from Pt-Y alloy formation, it is clear that the Pt-Y system is a promising ORR catalyst which merits further investigation. (C) 2010 Elsevier B.V. All rights reserved.