Probing the surface fine structure through electrochemical oscillations

Autor(es)

Previdello, B. A. F. ^[1] ; Fernandez, P. S. ^{[1, 2]} ; Tremiliosi-Filho, G. ^[1] ; Varela, H. ^[1]

Afiliação do(s) autor(es)

^[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

• Tipo de documento: Artigo Científico
• Fonte: Physical Chemistry Chemical Physics; v. 20, n. 8, p. 5674-5682, FEB 28 2018.
• Citações Web of Science: 1

Resumo

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)

• Processo FAPESP: 12/24152-1 - Cinética complexa em sistemas eletroquímicos: mecanismos, análise de redes estequiométricas e simulações numéricas
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• Modalidade de apoio: Bolsas no Exterior - Pesquisa
• Processo FAPESP: 16/01365-0 - Eletro-oxidação de glicerol sobre nanopartículas metálicas com interesse em ciência básica e aplicada. Coprodução de energia e de compostos de alto valor econômico
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• Processo FAPESP: 13/16930-7 - Eletrocatálise V: processos eletrocatalíticos de interconversão entre as energias química e elétrica
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• Processo FAPESP: 14/23073-6 - Eletro-oxidação de etanol sobre nanopartículas de PtNi: eletrocatálise e cinética não-linear
• Beneficiário: Bruno Alarcon Fernandes Previdello
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Pós-Doutorado