Nanogravimetric study of electrocatalytic oxidation of formic acid, methanol and glucose

• Grant number: 20/04646-6
• Support type: Scholarships in Brazil - Master
• Effective date (Start): November 01, 2020
• Effective date (End): July 31, 2021
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal researcher: Hamilton Brandão Varela de Albuquerque
• Grantee: Aryanne Viana
• Home Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

The electro-oxidation reactions of small organic molecules are studied under different catalysts and by means of techniques so that one can know the reaction mechanisms and the reaction intermediates. These reactions have some characteristics in common in their reaction mechanisms that are responsible for making the electro-oxidation processes susceptible to dynamic instabilities. The glucose electro-oxidation reaction is used in different applications and its use has been highlighted in fuel cells. On a polycrystalline and gold platinum electrode, the glucose oxidation mechanism occurs in three stages: dehydrogenation of the molecule; oxidation of glucose intermediates; and oxidation of the catalyst capable of promoting the catalysis of glucose oxidation. Electro-oxidation of formic acid on platinum is currently accepted as a parallel mechanism of three reaction pathways. The first pathway known as the direct pathway is the formation of reactive intermediates and have a very short half-life that does not allow their detection, the second pathway represented is the formation of the formate as an intermediate and this pathway is known as the formate pathway and the indirect route where there is an electrode block at low potentials due to the formation of COad. Electro-oxidation of methanol on platinum also passes the formation of carbon monoxide (CO), which is considered the catalytic poison of the reaction, and intermediate species of CHO and COH are formed that are weakly adsorbed to the electrode surface. The use of modified platinum electrodes can reveal important details of the mechanism, influencing, for example, the coverage of some intermediates. In this project, the objective is to study the catalytic process of the electro-oxidation reactions of glucose, formic acid and methanol molecules under different experimental conditions using Electrochemical Quartz Crystal Nanobalance (EQCN) to analyze variations in mass during the processes. (AU)