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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Probing the surface fine structure through electrochemical oscillations

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Author(s):
Previdello, B. A. F. [1] ; Fernandez, P. S. [1, 2] ; Tremiliosi-Filho, G. [1] ; Varela, H. [1]
Total Authors: 4
Affiliation:
[1] Univ Sao Paulo, Inst Chem Sao Carlos, POB 780, BR-13560970 Sao Carlos, SP - Brazil
[2] Univ Estadual Campinas, Inst Chem, Cidade Univ Zeferino Vaz, BR-13083970 Campinas, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Physical Chemistry Chemical Physics; v. 20, n. 8, p. 5674-5682, FEB 28 2018.
Web of Science Citations: 1
Abstract

In the course of (electro) catalytic reactions, reversible and irreversible changes, namely the formation of adsorbed poisons, catalyst degradation, surface roughening, etc., take place at distinct time-scales. Reading the transformations on the catalyst surface from the measurement of the reaction rates is greatly desirable but generally not feasible. Herein, we study the effect of random surface defects on Pt(100) electrodes toward the electro-oxidation of methanol in acidic media. The surface defects are gently generated in situ and their relative magnitudes are reproducibly controlled. The system was characterized under conventional conditions and investigated under an oscillatory regime. Oscillatory patterns were selected according to the presence of surface defects, and a continuous transition from large amplitude/low frequency oscillations (type L) on smooth surfaces to small amplitude/high frequency oscillations (type S) on disordered surfaces was observed. Importantly, self-organized potential oscillations were found to be much more sensitive to the surface structure than conventional electrochemical signatures or even other in situ characterization methods. As a consequence, we proved the possibility of following the surface fine structure in situ and in a non-invasive manner by monitoring the temporal evolution of oscillatory patterns. From a mechanistic point of view, we describe the role played by surface defects and of the adsorbed and partially oxidized, dissolved species on the oscillations of type S and L. (AU)

FAPESP's process: 12/24152-1 - Complex kinetics in electrochemical systems: mechanisms, stoichiometric network analysis and numerical simulations
Grantee:Hamilton Brandão Varela de Albuquerque
Support type: Scholarships abroad - Research
FAPESP's process: 16/01365-0 - Glycerol electro-oxidation on metallic nanoparticles with interest in basic as well as in applied science. Simultaneous production of energy and fine chemicals
Grantee:Pablo Sebastián Fernández
Support type: Program for Research on Bioenergy (BIOEN) - Regular Program Grants
FAPESP's process: 13/16930-7 - Electrocatalysis V: electrocatalytic processes of chemical and electrical energy interconversion
Grantee:Edson Antonio Ticianelli
Support type: Research Projects - Thematic Grants
FAPESP's process: 14/23073-6 - Ethanol electrooxidation on PtNi nanoparticles: electrocatalysis and non-linear kinetics
Grantee:Bruno Alarcon Fernandes Previdello
Support type: Scholarships abroad - Research Internship - Post-doctor