Full text
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| Author(s): |
Aryanne Viana
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Carlos. |
| Institution: | Universidade de São Paulo (USP). Instituto de Química de São Carlos (IQSC/BT) |
| Defense date: | 2022-12-12 |
| Examining board members: |
Hamilton Brandão Varela de Albuquerque;
Mauro Coelho dos Santos;
Elton Fabiano Sitta
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| Advisor: | Hamilton Brandão Varela de Albuquerque |
| Abstract | |
The electro-oxidation of glucose is an important reaction that finds applications in different areas such as the production of gluconate, the study and development of biosensors, micro-actuators, pacemakers and fuel cells. This dissertation presents a study of the catalytic process involving the electro-oxidation reaction of glucose on platinum and gold films by means of the Electrochemical Quartz Crystal Nanobalance, EQCN. In addition to the cyclic voltammetry experiments, the oscillatory processes involved in this reaction were investigated. The results obtained showed that the dynamics of the oscillatory electro-oxidation of glucose depends critically on the type of electrode used and, on the nature, and concentration of the species present in the electrolyte. In general terms, a rich oscillatory dynamic of the electro-oxidation of glucose on platinum was observed in alkaline KOH electrolyte. For [glucose] = 1 mol L-1, a frequency variation in phase with the potential oscillations was observed. Thus, as the potential increased, the mass of the electrode surface decreased. As for gold, this behavior was not observed and the oscillations were considerably simpler. In this case, the frequency variation presents a trend profile that is in phase with the potential oscillations, but there is the occurrence of noise in the same amplitude as the f values, making it difficult to distinguish between what is in fact noise and what is a mass variation of the system. The experiments, then, allowed to corroborate the existence of different mechanisms of electro-oxidation of glucose under Pt and Au surface in which the process on platinum occurs by the adsorption of glucose molecules directly on the surface, while, in gold, the oxidation of glucose takes place on the oxygenated species formed. Additional tests with polyaniline-modified platinum (PANI) surfaces revealed no catalytic effects of the Pt/PANI electrode for glucose electro-oxidation, probably due to the difficulty of glucose to penetrate the polymer matrix. (AU) | |
| FAPESP's process: | 20/04646-6 - Nanogravimetric study of electrocatalytic oxidation of formic acid, methanol and glucose |
| Grantee: | Aryanne Viana |
| Support Opportunities: | Scholarships in Brazil - Master |