Electrocatalytic Oxidation of Formic Acid at an Ordered Intermetallic PtBi Surface

• Published in: Chemphyschem Vol. 4; no. 2; pp. 193 - 199
• Main Authors: Casado-Rivera, Emerilis, Gál, Zoltán, Angelo, A. C. D., Lind, Cora, DiSalvo, Francis J., Abruña, Héctor D.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 17.02.2003; WILEY‐VCH Verlag
• Subjects: electrocatalysis; electrochemistry; metals; oxidation; surfaces
• ISSN: 1439-4235; 1439-7641
• DOI: 10.1002/cphc.200390030

The electrocatalytic oxidation of formic acid at a PtBi ordered intermetallic electrode surface has been investigated using cyclic voltammetry, rotating disk electrode (RDE) voltammetry and differential electrochemical mass spectrometry (DEMS). The results are compared to those at a polycrystalline platinum electrode surface. The PtBi electrode exhibits superior properties when compared to polycrystalline platinum in terms of oxidation onset potential, current density, and a much diminished poisoning effect by CO. Using the RDE technique, a value of 1.4×10−4 cm s−1 was obtained for the heterogeneous charge transfer rate constant. The PtBi surface did not appear to be poisoned when exposed to a CO saturated solution for periods exceeding 0.5 h. The results for PtBi are discussed within the framework of the dual‐path mechanism for the electrocatalytic oxidation of formic acid, which involves formation of a reactive intermediate and a poisoning pathway. Burns better with mixed metals. The electrocatalytic oxidation of formic acid, of great interest for fuel cell applications, proceeds more robustly at a PtBi ordered intermetallic electrode surface compared to that at a polycrystalline platinum electrode surface. The PtBi electrode exhibits superior oxidation onset potential and current density (the cyclic voltammograms shown compare a Pt with a PtBi electrode) and does not appear to be poisoned when exposed to a CO‐saturated solution even after 1 h.