Activity and Long-Term Stability Study of Pt-Y/C Electrocatalysts for Oxygen Reduction Reaction

Pt-Y/C catalysts were prepared by a modified formic acid method and their activities for oxygen reduction reaction (ORR) were evaluated. X-ray diffraction analysis showed that no alloy was formed between the metals, while x-ray photoelectron spectroscopy revealed that yttrium is present as Y2O3, Y(OH)(3), and Y-O-Pt. The Pt-Y/C 7:3 material had the highest specific activity (94 mu A cm(Pt)(-2)) for ORR, and was superior to other PtY/C materials. Following repetitive potential cycling, ORR activity of the Pt-Y/C 7:3 catalyst decreased in a similar proportion to that of Pt/C. X-ray photoelectron spectroscopy results of the aged ultrathin catalyst layer were in agreement with energy-dispersive x-ray spectroscopy data. These studies revealed that the intensities of the Y 3d peaks were suppressed due to voltammetric cycling and that while Y2O3 and Y(OH)(3) dissolved, Y-O-Pt remained in the catalyst. (AU)