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摘要:
The electrochemical oxygen reduction at PtBi ordered intermetallic electrode surface has been investigated using cyclic voltammetry and rotating disk electrode. The results are compared to those at a polycrystalline platinum electrode surface. It was found that in methanol containing electrolyte solution the onset potential for oxygen reduction at PtBi is shifted to more positive potentials and the PtBi catalyst has about 4 times higher limiting current density for oxygen reduction than Pt. Thus the PtBi electrode exhibits superior properties in 0.5 mol center dot L-1 H2SO4 + 0.25 mol center dot L-1 CH3OH when compared to polycrystalline platinum in terms of oxygen reduction onset potential band current density. In ordered intermetallic PtBi, the Pt-Pt bond length is increased to 0.432 nm. This expansion makes it very difficult for methanol to adsorb on the PtBi surface, leading the PtBi to have the ability of resisting methanol. X-ray photoelectron spectroscopy analysis indicated an increased d-electron vacancy of the Pt in PtBi. Such an increase of 5 d vacancies led to an increased 2 pi electron donation from O-2 to the Pt, resulting in an increased O-2 adsorption and a weakened O-O bond.
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来源 :
ACTA PHYSICO-CHIMICA SINICA
ISSN: 1000-6818
年份: 2005
期: 3
卷: 21
页码: 287-290
1 0 . 9 0 0
JCR@2022
ESI学科: CHEMISTRY;
JCR分区:4