Issue 6, 2005

Electro-oxidation of carbon monoxide and methanol on bare and Pt-modified Ru(10[1 with combining macron]0) electrodes

Abstract

The activity towards CO and methanol electrooxidation of bare and platinum-modified Ru(10[1 with combining macron]0) surfaces has been investigated. The structure/morphology and composition of the modified surfaces were characterized using electron diffraction techniques (LEED, RHEED) and Auger spectroscopy. The bare Ru(10[1 with combining macron]0) surface exhibits a higher catalytic activity towards CO electrooxidation than the Ru(0001) surface due to the lower oxidation potential of the former surface. The early stages of surface oxidation lead to disordering of the surface and further enhancing of the electrocatalytic activity. Electrodeposition of Pt on Ru(10[1 with combining macron]0) leads to epitaxial growth via a Volmer–Weber growth mode. The Pt clusters grow preferentially with the (311) plane parallel to the substrate surface with (0[1 with combining macron]1) rows in the layers in contact with the substrate compressed by about 3% with respect to bulk Pt, in order to match with the (12[1 with combining macron]0) rows of the Ru(10[1 with combining macron]0) surface. This compression leads to enhanced catalytic activity towards CO oxidation for thin Pt deposits whereas for large deposited Pt particles the dominating factor for the catalytic enhancement is the higher concentration of surface defects. On the other hand, in the case of methanol oxidation, the dominant factor in determining the catalytic activity is the concentration of adjacent Pt–Ru sites, although surface defects play an important role in the methanol dehydrogenation steps.

Graphical abstract: Electro-oxidation of carbon monoxide and methanol on bare and Pt-modified Ru(10 [[1 with combining macron]] 0) electrodes

Article information

Article type
Paper
Submitted
26 jul 2004
Accepted
20 jan 2005
First published
07 feb 2005

Phys. Chem. Chem. Phys., 2005,7, 1300-1309

Electro-oxidation of carbon monoxide and methanol on bare and Pt-modified Ru(10[1 with combining macron]0) electrodes

A. L. N. Pinheiro, M. S. Zei and G. Ertl, Phys. Chem. Chem. Phys., 2005, 7, 1300 DOI: 10.1039/B411467A

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