Halide adsorption effect on methanol electro-oxidation reaction studied by dynamic instabilities

Autor(es)

Fiori, I. A. ^[1] ; Melle, G. B. ^{[2, 1]} ; Sitta, E. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Chem Dept, Rod Washington Luis, Km 235, BR-235 Sao Carlos, SP - Brazil

^[2] Univ Sao Paulo, Chem Inst Sao Carlos, Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF ELECTROANALYTICAL CHEMISTRY; v. 856, JAN 1 2020.
• Citações Web of Science: 0

Resumo

The effect of halide anion adsorption on methanol electro-oxidation reaction in acid media was studied by means of thermal effects on both cyclic voltammograms (CV) and oscillations in galvanostatic time series (GTS). While increasing the chloride concentration we observed a monotonically current decrease followed by an increase of apparent activation energy (E-a) in CV, GTS increases the maximum potential (E-max) and decreases both the oscillation frequency (w) and E-a. Poisoning/Freeing rates (dE/dt) increase for a very small Cl- amount but decreases for higher concentrations. Changing Cl- by Br-, albeit observing similar behaviors for currents on CV and w, E-max and E-a changes suggest that Br- probably plays a dual role, i.e. poisoning the surface by its adsorption but also interacting with adsorbed methanol residues. Finally, increasing the pH to 5.6 in a nonadsorbing electrolyte (HClO4/NaF) several oscillations patterns were mapped with a lesser Cl- influence on both CV and GTS. (C) 2019 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 13/07296-2 - CDMF - Centro de Desenvolvimento de Materiais Funcionais
• Beneficiário: Elson Longo da Silva
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs