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Effect of the Random Defects Generated on the Surface of Pt(111) on the Electro‐oxidation of Ethanol: An Electrochemical Study
Author(s) -
Barbosa Amaury F. B.,
Del Colle Vinicius,
GómezMarín Ana M.,
Angelucci Camilo A.,
TremiliosiFilho Germano
Publication year - 2019
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.201900544
Subject(s) - electrochemistry , chemistry , ethanol , platinum , inorganic chemistry , materials science , analytical chemistry (journal) , electrode , catalysis , organic chemistry
In the present work, the Pt(111) surface was disordered by controlling the density of {110}‐ and {100}‐type defects. The cyclic voltammogram (CV) of a disordered surface in acid media consists of three contributions within the hydrogen adsorption/desorption region: one from the well‐ordered Pt(111) symmetry and the other two transformed from the {111}‐symmetry with contributions of {110}‐ and {100}‐type surface defects. The ethanol oxidation reaction (EOR) was studied on these disordered surfaces. Electrochemical studies were performed in 0.1 M HClO 4 +0.1 M ethanol using cyclic voltammetry and chronoamperometry. Changes in current densities associated to the specific potentials at which each oxidation peak appears suggest that different surface domains of disordered platinum oxidize ethanol independently. Additionally, as the surface‐defect density increases, the EOR is catalysed better. This tendency is directly observed from the CV parameters because the onset and peak potentials are shifted to less positive values and accompanied by increases in the oxidation‐peak current on disordered surfaces. Similarly, the CO oxidation striping confirmed this same tendency. Chronoamperometric experiments showed two opposite behaviors at short oxidation times (0.1 s). The EOR was quickly catalyzed on the most disordered surface, Pt(111)‐16, and was then rapidly deactivated. These results provide fundamental information on the EOR, which contributes to the atomic‐level understanding of real catalysts.