Banca de QUALIFICAÇÃO: TAMIRES FERREIRA DA COSTA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : TAMIRES FERREIRA DA COSTA
DATA : 07/12/2017
HORA: 15:00
LOCAL: Auditório do NUPPRAR
TÍTULO:

Experimental and theoretical study of interactions of chemical species on the surface of the boron-doped diamond electrode to promote the formation of strongly oxidant species

PALAVRAS-CHAVES:

BDD, oxalic acid, surfaces, interactions

PÁGINAS: 90
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Físico-Química
ESPECIALIDADE: Eletroquímica
RESUMO:

Diamond is an allotropic form of carbon formed by single bonds (sp3 hybridization) between carbons in a tetrahedral geometry, possessing unique properties such as high thermal conductivity, hardness, flexural strength, mechanical resistivity and chemical inertness. Due to these properties, the diamond (natural or synthetic) is used in various technological sectors such as mechanical, electronic, optical, chemical, medical and space. Due to the absence of electrical conductivity on diamond, a doping is necessary with boron, nitrogen or fluorine, giving metallic semiconductor characteristics according to the amount of those elements present onto it. Among the cited elements, boron is the most used. After the optimization of the preparation of synthetic diamond films, these materials were greatly used for different investigations and technological applications. In electrochemistry, diamond films received special attention due to their peculiar properties (low-current capacitive; wide window of potential in aqueous medium; fast electron transfer kinetics in multiple redox systems; weak molecular adsorption (low passivation) and corrosion resistance), principally when diamond surfaces doped with boron were employed. First studies using boron doped diamond (BDD) were performed for investigating the electrochemical behavior of redox systems on its surface, and, consequently, its application with other analytical techniques. For this reason, the use of these materials in the electroanalysis was superior to other forms of carbon (graphite, glassy carbon, etc.). After that, some researchers determined that BDD films can be used to oxidize organic compounds, obtaining complete removal of them from solution. These results have clearly showed that BDD film electrodes, when act as anode, they possess a high stability in strong acid aqueous media producing hydroxyl radicals (●OH) during the oxidation of water. These radicals are physically absorbed on the BDD surface. ●OH radicals are considered strong oxidants, and when produced at BDD surface, the degradation of organic compounds can be achieved efficiently. Additionally, the production of other strong oxidants species is possible by participation of ●OH radicals, such as, active chlorine, ozone, hydrogen peroxide, persulphate, percarbonate, among others. However, recent studies have demonstrated that the mechanisms of oxidation of organic compounds as well as the formation of the oxidizing strong species are strongly influenced by the characteristics of conductive layer and the substrate properties of diamond anodes. In this way, the main objective of this project is to study by experimental procedures and theoretical calculations the interactions of different species on the surface of diamond electrode. The investigation of these parameters allows to understand the formation of strong oxidant species as well as the electrochemical oxidation mechanisms of organic compounds that occurs via conversion or electrochemical combustion.

MEMBROS DA BANCA:
Presidente - 1645110 - CARLOS ALBERTO MARTINEZ HUITLE
Interno - 1959889 - DAVI SERRADELLA VIEIRA
Externo ao Programa - 1149539 - MARIA GORETTE CAVALCANTE