CO adsorption and oxidation on a Pt(111) electrode modified by ruthenium deposition: an IR spectroscopic study
1996; Elsevier BV; Volume: 402; Issue: 1-2 Linguagem: Inglês
10.1016/0022-0728(95)04237-7
ISSN1873-2569
AutoresK. Andreas Friedrich, K.P. Geyzers, U. Linke, Ulrich Stimming, Jürgen Stumper,
Tópico(s)Electrochemical Analysis and Applications
ResumoCO adsorption and electro-oxidation on a Pt(111) electrode modified by Ru deposition was studied by IR spectroscopy. The IR spectra in the region of the CO stretching vibration exhibit distinct bands which can be assigned to CO adsorbed on the Pt substrate (CO|Pt) and on Ru islands (CO|Ru). This is in contrast with IR studies of Pt Ru alloy electrodes where only a single vibrational band of adsorbed CO is observed. The integrated band intensities of the CO|Ru and of CO|Pt bands on the Ru-modified Pt(111) electrode decrease simultaneously at the onset potential of CO oxidation. The results are interpreted within the framework of a bifunctional mechanism of CO electro-oxidation, postulating active Pt sites in close proximity to the Ru islands and a high mobility of the CO|Pt adsorbate layer. The differences in the IR spectra between the Ru|Pt(111) electrode and the Pt Ru alloys are explained by disparate surface structures (Ru islands versus homogeneous distribution of Pt and Ru atoms).
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