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| Author(s): |
Adriano Lopes Santos
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: | 2010-06-18 |
| Examining board members: |
Hamilton Brandão Varela de Albuquerque;
Fritz Cavalcante Huguenin
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| Advisor: | Hamilton Brandão Varela de Albuquerque |
| Abstract | |
In times where the society turns its reflections on climate and energy questions, fuel cells appear as a promising alternative for the policies aimed at sustainable development. In this sense, there are still challenges to overcome in fundamental and applied levels. Understand the role of species in the supporting electrolyte is crucial in such a description. Specifically in the case of anions dissolved in the electrolyte, the most commonly assigned role is to inhibit the electrocatalytic process of interest, through blockade of surface sites. However, to the anion BF4- is recently attributed a diverse effect, the increase of the current values of electro-oxidation at low potentials. It is presented in this dissertation, a systematic study of this process, using the technique of the electrochemical quartz crystal nanobalança (EQCN), combined with traditional electrochemical techniques. This study revealed the occurrence of remarkable differences in the voltamassometric profiles of the electrochemical system when adding small amounts of reagent HBF4. Such differences are special features, since in the voltammetric profiles marked differences are not observed in current values between the electrochemical system with or without the addition of small amounts of reagent HBF4. On the basis of methods utilized and the experimental evidence observed, it is possible to infer that the peculiar behavior previously attributed to HBF4 actually results from a semimetal contamination with arsenic, although the manufacturer\'s label gives no information about the occurrence of traces of the semimetal. (AU) | |
| FAPESP's process: | 07/06037-2 - Nanogravimetric study of the surface electrooxidation process of gold |
| Grantee: | Adriano Lopes Santos |
| Support Opportunities: | Scholarships in Brazil - Master |