Mechanistic aspects of the comparative oscillatory electrochemical oxidation of formic acid and methanol on platinum electrode

Author(s)

Perini, Nickson ^[1] ; Delmonde, Marcelo V. F. ^{[2, 3]} ; Ranjan, Chinmoy ^[4] ; Varela, Hamilton ^{[2, 5]}

Affiliation

^[1] Univ Fed Sao Carlos, BR-13565905 Sao Carlos, SP - Brazil

^[2] Univ Sao Paulo, Inst Chem Sao Carlos, POB 780, BR-13560970 Sao Carlos, SP - Brazil

^[3] Fed Inst Educ Sci & Technol Parana, Umuarama, PR - Brazil

^[4] Indian Inst Sci, Dept Inorgan & Phys Chem, Banagalore 560012 - India

^[5] Max Planck Inst Phys Komplexer Syst, Nothnitzer Str 38, D-01187 Dresden - Germany

• Document type: Journal article
• Source: Journal of Solid State Electrochemistry; v. 24, n. 8, SI MAY 2020.
• Web of Science Citations: 1

Abstract

The characteristics of the electrochemical oscillations that emerge along the catalytic oxidation of small organic molecules critically depend on the coverage and nature of adsorbates. Herein we report experimental results on the electro-oxidation of formic acid and methanol on platinum and platinum-modified electrodes, and under conventional, i.e., cyclic voltammetry, and oscillatory conditions. The investigation was focused on the role played by surface-free sites and the presence of a step with a short-lived specie adsorbed on electrode surface. In order to reduce the coverage of adsorbed species, and thus to increase the main reaction pathway, chronoamperometry in platinum oxide region followed by potential sweeps or the adsorption of ad atoms, like tin, to mitigate the surface poisoning was adopted. Overall, those strategies considerably improved the electrochemical oxidation of formic acid, but had no effect for methanol. Our results show that the efficiency of formic acid electro-oxidation is preferred powered, compared with methanol, on a less poisoned electrode surface, which is obtained through a self-cleaning process driven by the oscillatory electro-oxidation of organic molecules. These results are rationalized in terms of peculiarities of the reaction mechanisms of both systems. (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: 13/16930-7 - Electrocatalysis V: electrocatalytic processes of chemical and electrical energy interconversion
• Grantee: Edson Antonio Ticianelli
• Support type: Research Projects - Thematic Grants