Hydrogen electrooxidation over palladium-gold alloy: Effect of pretreatment in ethylene on catalytic activity and CO tolerance

Alexander N. Simonov, Pavel E. Plyusnin, Yury V. Shubin, Ren I. Kvon, Sergey V. Korenev, Valentin N. Parmon

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Abstract

Palladium gold alloy powder (PdAu 2) was synthesized by reduction of the [Pd(NH 3) 4][AuCl 4] 2 complex with H 2 at 90°C, and then was additionally heated in a C 2H 4 (PdAu 2-C x) or H 2 flow (PdAu 2-H 2) at 300°C. The samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and by a set of electrochemical methods. The Pd:Au ratio on the surface of the PdAu 2 alloy suffers marginal changes after heating under C 2H 4 atmosphere, and decreases as a result of heating in a H 2 flow. Hydrogen oxidation reaction (HOR) over the catalysts was studied using rotating disk electrode at 25°C in 0.1 M HClO 4 in pure H 2 and in the presence of 1100 ppm of CO. Heat-treatment of the PdAu 2 alloy under H 2 does not improve its HOR activity and CO tolerance (normalized to Pd and total metal surface area), while the PdAu 2-C x catalyst exhibits substantially enhanced catalytic performance in the HOR both in the absence and in the presence of CO as compared to the parent PdAu 2 alloy. The enhanced activity of the C 2H 4-treated PdAu 2 alloy is explained by the promoting action of carbon atoms incorporated into the alloy structure during treatment under C 2H 4 atmosphere. This supposition is approved by the fact that mild oxidative treatment of the PdAu 2-C x sample degrades notably its catalytic activity.

Original languageEnglish
Pages (from-to)344-353
Number of pages10
JournalElectrochimica Acta
Volume76
DOIs
Publication statusPublished - 1 Aug 2012
Externally publishedYes

Keywords

  • CO tolerance
  • Hydrogen electrooxidation
  • Interstitial carbon
  • Palladium-gold alloy

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