Electro-Oxidation of Ethanol in Alkaline Medium: Complex Kinetics and Electrocatalysis

Author(s)

Loriz Francisco Sallum

• Document type: Doctoral Thesis
• Press: São Carlos.
• Institution: Universidade de São Paulo (USP). Instituto de Química de São Carlos (IQSC/BT)
• Defense date: 2018-09-14

Examining board members

Ernesto Rafael Gonzalez; Paulo Olivi; Lucia Helena Mascaro Sales; Juarez Lopes Ferreira da Silva

• Advisor: Ernesto Rafael Gonzalez

Abstract

The electro-oxidation of ethanol is certainly one of the main research topics in the field of electrocatalysis due to its potential use in converting chemical energy into electrical energy, since it is considered a renewable fuel with low toxicity and high energy density. When it is far from the thermodynamic equilibrium, this system presents a complex dynamic due to the continuous activation and deactivation of the catalyst and with the emergence of instabilities it is possible to achieve a higher thermodynamic efficiency when compared to the same system operating in conventional regime. In addition, the facility in which instabilities emerge and the simplicity which the experimental parameters can be controlled make the study of such systems attractive to the scientific community. In this thesis the results obtained during the conventional and non-linear dynamics of the electro-oxidation of ethanol in alkaline media are presented, combining the data obtained in both kinetic processes to fully understand the effect of the cations during the catalytic reaction. Once the impact of different ions on conventional and complex kinetics was analyzed, the maximum values of the turnover frequencies in the presence of different anions and cations were estimated using the data obtained by electroanalytical methods and, with the results in hand it was possible to discuss the activity on a more fundamental basis . Also, from the data of the oscillatory dynamics, it was possible to perform an indirect evaluation of the chemical dissipation of the systems studied using the pseudo-stationary curves. Finally, the characterization of the oscillatory behavior of the electro-oxidation of ethanol in alkaline medium on platinum single-crystalline surfaces was performed, connecting the disparities in the oscillatory profile with the defects presented in each crystallographic planes. (AU)

• FAPESP's process: 13/24162-0 - Electro-oxidation of small organic molecules in alkaline medium: complex kinetics and electrocatalysis
• Grantee: Loriz Francisco Sallum
• Support Opportunities: Scholarships in Brazil - Doctorate