Electrochemical oxidation of sulfamethazine on a glassy carbon electrode modified with graphene and gold nanoparticles
This work presents a comprehensive investigation of the oxidation mechanism of sulfamethazine (SMZ) combining electrochemical experiments and molecular modelling techniques. Cyclic voltammetry and differential pulse voltammetry experiments were performed in phosphate buffer solution (PBS) using a gl...
| Autores: | , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2016 |
| País: | Brasil |
| Institución: | Universidade Estadual Paulista (UNESP) |
| Repositorio: | Repositório Institucional da UNESP |
| Idioma: | inglés |
| OAI Identifier: | oai:repositorio.unesp.br:11449/172504 |
| Acceso en línea: | http://dx.doi.org/10.1016/j.electacta.2016.01.178 http://hdl.handle.net/11449/172504 |
| Access Level: | acceso abierto |
| Palabra clave: | Density Functional Theory Electronic structure calculations Fukui indexes Oxidation mechanisms Sulfamethazine |
| Sumario: | This work presents a comprehensive investigation of the oxidation mechanism of sulfamethazine (SMZ) combining electrochemical experiments and molecular modelling techniques. Cyclic voltammetry and differential pulse voltammetry experiments were performed in phosphate buffer solution (PBS) using a glassy carbon (GC) electrode modified with reduced graphene oxide and gold nanoparticles (rGO-AuNPs). Molecular modelling studies were performed via Density Functional Theory (DFT) employing Becke's LYP (B3LYP) exchange-correlation functional and the 6-31G(p,d) basis set. The evaluation of molecular reactivity was accomplished by Condensed-to-Atoms Fukui Indexes (CAFIs). In the theoretical studies, three species were analysed: natural SMZ (SMZ(0)) and its protolytic structures, SMZ(+H) and SMZ(-H). The CV results show a well-defined irreversible SMZ oxidation peak at +0.89 V. The molecular modelling studies indicate that SMZ(0) is the species that effectively participates in the oxidation process. Based on the reactivity indexes obtained, two distinct oxidation mechanisms associated with EC processes occurring in the systems were proposed. |
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