Banca de DEFESA: JÉSSICA FRANÇA DE OLIVEIRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : JÉSSICA FRANÇA DE OLIVEIRA
DATA : 02/08/2019
HORA: 14:00
LOCAL: Sala de seminários - Instituto de Química
TÍTULO:

Investigation of the electrochemical synthesis on the capacitive properties of RuO₂ and RuO₂-WO₃ electrodes

PALAVRAS-CHAVES:

electrochemical capacitors

RuO₂

electrodeposition

factorial design

PÁGINAS: 120
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Físico-Química
ESPECIALIDADE: Eletroquímica
RESUMO:

     Electrochemical capacitors have been presented several advantages on the conventional storage devices, such as batteries and capacitors. Studies have shown that among the electrochemical capacitors, the pseudocapacitor materials based on transition metal oxide, in particular RuO₂, are the most promising, exhibiting high values of specific capacitance and long-life cycles. However, ruthenium oxide presents a high cost as main disadvantage due to its low natural abundance. On the other hand, the tungsten oxide, WO3, still little studied for this application, can also be used as pseudocapacitors. In this sense, we proposed the electrochemical synthesis of RuO₂-WO₃ mixed oxides, in order to investigate a possible reduction of costs, maintaining the desired capacitive properties for the electrode material. Since it is known that the preparation variables strongly influence the final characteristics of the electrodeposited oxides, it is of fundamental importance to know these relations with the properties of the material in order to make the synthesis process more efficient and to obtain more efficient materials to the application as capacitor. The best way for this whole process to be mapped is to use factorial design as a tool for analysis and optimization. Thus, in this work, we propose the analysis of the preparation variables (scan rate, cycles numbers and deposition temperature) for the synthesis by the cyclic voltammetry of mixed oxides of nominal ratio 1: 1 (RuO₂: WO₃). This study was carried out from a factorial design 2³ and the specific capacitance was used as response factor. The analysis by factorial design revealed that the variables that the most influence on the specific capacitance values are scan rate and cycles number, in this order. Once the optimum conditions for the system were found, a study of the proportions of the metals in the original electrolytic solution was carried out. This study showed that the higher the proportion of ruthenium oxide the higher the specific capacitance values, however, acceptable values of specific capacitance were obtained with compositions up to 70:30 (RuO₂: WO₃).

MEMBROS DA BANCA:
Presidente - 1488945 - ADRIANE VIANA DO ROSARIO
Interno - 1861434 - VALERIA CRISTINA FERNANDES
Interno - 2362069 - RAILDO ALVES FIUZA JUNIOR
Interno - 2356272 - ARTUR JOSE SANTOS MASCARENHAS
Externo à Instituição - FERNANDO HENRIQUE CRISTOVAN - UFG
Externo à Instituição - ERNESTO CHAVES PEREIRA DE SOUZA - UFSCAR