Acta Phys. -Chim. Sin. ›› 2005, Vol. 21 ›› Issue (03): 287-290.doi: 10.3866/PKU.WHXB20050312

• ARTICLE • Previous Articles     Next Articles

Intermetallic PtBi as Methanol-tolerant Catalysts for Oxygen Reduction

ZHANG Li-Juan; XIA Ding-Guo; WANG Zhen-Yao; YUAN Rong; WU Zi-Yu   

  1. College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100022
  • Received:2004-07-14 Revised:2004-10-20 Published:2005-03-15
  • Contact: ZHANG Li-Juan

Abstract: 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•L-1 H2SO4+0.25 mol•L-1 CH3OH when compared to polycrystalline platinum in terms of oxygen reduction onset potential and 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 5d vacancies led to an increased 2π electron donation from O2 to the Pt, resulting in an increased O2 adsorption and a weakened O-O bond.

Key words: Electrocatalysis, PtBi, Intermetallic compounds