Carbon supported Pt-Y electrocatalysts for the oxygen reduction reaction

摘要

Carbon supported Pt_3Y(Pt_3Y/C) and PtY(PtY/C) were investigated as oxygen reduction reaction (ORR)cat- alysts. After synthesis via reduction by NaBH_4, the alloy catalysts exhibited 10-20% higher mass activity (mA mgpt~(-1)) than comparably synthesized Pt/C catalyst. The specific activity (μAcm_(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 ℃ under a reducing atmosphere, Pt_3Y/C-900 and PtY/C-900 catalysts showed improved ORR activity; the Pt/C and Pt/C-900 (Pt/C catalyst annealed at 900 ℃) catalysts exhibited specific activities of 334 and 393 μA cm_(pt)~(-2), respectively, while those of the Pt_3 Y/C-900 and PtY/C-900 catalysts were 492 and 1050μA cm_(pt)~(-2), respectively. X-ray diffraction results revealed that both the Pt_3Y/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_3Y/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.