Carbon supported Pt–Y electrocatalysts for the oxygen reduction reaction

Carbon supported Pt3Y (Pt3Y/C) and PtY (PtY/C) were investigated as oxygen reduction reaction (ORR) catalysts. After synthesis via reduction by NaBH4, the alloy catalysts exhibited 10–20% higher mass activity (mA mgPt−1) than comparably synthesized Pt/C catalyst. The specific activity (μA cmPt−2) was 23 and 65% higher for the Pt3Y/C and PtY/C catalysts, respectively, compared to Pt/C. After annealing at 900 °C under a reducing atmosphere, Pt3Y/C-900 and PtY/C-900 catalysts showed improved ORR activity; the Pt/C and Pt/C-900 (Pt/C catalyst annealed at 900 °C) catalysts exhibited specific activities of 334 and 393 μA cmPt−2, respectively, while those of the Pt3Y/C-900 and PtY/C-900 catalysts were 492 and 1050 μA cmPt−2, respectively. X-ray diffraction results revealed that both the Pt3Y/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 Pt3Y/C-900 catalyst, while the PtY/C-900 catalyst remained unchanged. Although these results suggested that the high ORR activity 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.