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Influence of Substrate Steps on the Catalytic Properties of Pt Layers: The Ethanol Electrooxidation Reaction
Author(s) -
Prieto Mauricio J.,
TremiliosiFilho Germano
Publication year - 2014
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201402377
Subject(s) - catalysis , chemistry , substrate (aquarium) , monolayer , crystallography , epitaxy , molecule , inorganic chemistry , analytical chemistry (journal) , organic chemistry , layer (electronics) , biochemistry , oceanography , geology
The ethanol oxidation reaction (EOR) is investigated on Pt/Au(hkl) electrodes. The Au(hkl) single crystals used belong to the [ n (111) x (110)] family of planes. Pt is deposited following the galvanic exchange of a previously deposited Cu monolayer using a Pt 2+ solution. Deposition is not epitaxial and the defects on the underlying Au(hkl) substrates are partially transferred to the Pt films. Moreover, an additional (100)‐step‐like defect is formed, probably as a result of the strain resulting from the Pt and Au lattice mismatch. Regarding the EOR, both vicinal Pt/Au(hkl) surfaces exhibit a behavior that differs from that expected for stepped Pt; for instance, the smaller the step density on the underlying Au substrate, the greater the ability to break the CC bond in the ethanol molecule, as determined by in situ Fourier transform infrared spectroscopy measurements. Also, we found that the acetic acid production is favored as the terrace width decreases, thus reflecting the inefficiency of the surface array to cleave the ethanol molecule.