Composition effects of FePt alloy nanoparticles on the electro-oxidation of formic acid

Wei Chen, Jaemin Kim, Shouheng Sun, Shaowei Chen

Research output: Contribution to journalArticlepeer-review


The catalytic activities of Fe xPt 100-x alloy nanoparticles at different compositions (x = 10, 15, 42, 54, 58, and 63) in the electro-oxidation of formic acid have been investigated by using cyclic voltammetry (CV), chronoamperometry, and electrochemical impedance spectroscopy (EIS). It was observed that the electrocatalytic performance was strongly dependent on the FePt particle composition. In chronoamperometric measurements, the alloy particles at x ≈ 50 showed the highest steady-state current density among the catalysts under study and maintained the best long-term stability. In addition, on the basis of the anodic peak current density, onset potentials, and the ratios of the anodic peak current density to the cathodic peak current density in CV studies, the catalytic activity for HCOOH oxidation was found to decrease in the order Of Fe 42Pt 58 > Fe 54Pt 46 ≈ Fe 58Pt 42 > Fe 15Pt 85 > Fe 10Pt 90 > Fe 63Pt 37. That is, within the present experimental context, the alloy nanoparticles at x ≈ 50 appeared to exhibit the maximum electrocatalytic activity and stability with optimal tolerance to CO poisoning. Consistent responses were also observed in electrochemical impedance spectroscopic measurements. For the alloy nanoparticles that showed excellent tolerance to CO poisoning, the impedance in the Nyquist plots was found to change sign from positive to negative with increasing electrode potential, suggesting that the electron-transfer kinetics evolved from resistive to pseudoinductive and then to inductive characters. However, for the nanoparticles that were heavily poisoned by adsorbed CO species during formic acid oxidation, the impedance was found to be confined to the first quadrant at all electrode potentials. The present work highlights the influence of the molecular composition of Pt-based alloy electrocatalysts on the performance of formic acid electro-oxidation, an important aspect in the design of bimetal electrocatalysts in fuel cell applications.

Original languageEnglish (US)
Pages (from-to)11303-11310
Number of pages8
Issue number22
StatePublished - Oct 23 2007
Externally publishedYes

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry


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