Structure effects on electrocatalysts. Oxygen redu... - BV FAPESP
Advanced search
Start date
Betweenand
Related content
(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Structure effects on electrocatalysts. Oxygen reduction on Te-modified Pt(111) surfaces: Site-blocking vs electronic effects

Full text
Author(s):
Gomez-Marin, Ana Maria [1] ; Briega-Martos, Valentin [2] ; Feliu, Juan M. [2]
Total Authors: 3
Affiliation:
[1] Technol Inst Aeronaut ITA, Dept Chem, Div Fundamental Sci IEF, BR-12228900 Sao Jose Dos Campos, SP - Brazil
[2] Univ Alicante, Inst Electroquim, Apt 99, E-03080 Alicante - Spain
Total Affiliations: 2
Document type: Journal article
Source: Journal of Chemical Physics; v. 152, n. 13 APR 7 2020.
Web of Science Citations: 0
Abstract

In this work, the oxygen reduction reaction (ORR) on tellurium-modified Pt(111) surfaces has been studied. Adsorption of Te adatoms on Pt(111) progressively shifts toward less positive values of both the ORR reaction onset and the half-wave potential in 0.1M HClO4 for 0 < <theta>(Te) < 0.25. However, at <theta>(Te) > 0.25, the ORR activity increases relative to the one at theta (Te) < 0.25, but remains lower than that on clean Pt(111). Results were analyzed in light of simulations of kinetic currents as a function of <theta>(Te), calculated by employing a simple mean field model including both site blocking and electronic effects. Inside this framework, experimental data are best explained by considering that oxygenated Te species inhibit the ORR by either negatively modifying adsorption energies of reaction intermediates or combined site-blocking and electronic effects. A redox ORR catalysis due to redox properties of Te adatoms is discarded. Contrarily, in 0.05M H2SO4, a positive catalytic effect has been found, interpreted in terms of a competitive adsorption-desorption mechanism involving the replacement of adsorbed sulfate by Te adatoms. On the other hand, despite the strong site-blocking effect on H-ads and OHads adsorption by Te adatoms, it appears that the reduced Te-Pt(111) adlayer does not inhibit the reaction, suggesting different active sites for H-ads and OHads adsorption and for the rate-determining step of the ORR mechanism. (AU)

FAPESP's process: 19/04484-9 - In situ characterization of the oxygen reduction reaction on carbon based materials by Shell-isolated nanoparticle-enhanced Raman spectroscopy
Grantee:Ana Maria Gómez Marín
Support Opportunities: Scholarships abroad - Research