• JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
 
  Bookmark and Share
 
 
Master's Dissertation
DOI
Document
Author
Full name
Geovanne Lemos de Assis
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2019
Supervisor
Committee
Araki, Koiti (President)
Hewer, Thiago Lewis Reis
Peres, Henrique Estanislau Maldonado
Title in Portuguese
Alfa-hidróxido misto de níquel/cério como eletrocatalisador para oxidação de álcoois
Keywords in Portuguese
Álcoois
Células a combustível
Eletrocatálise
Materiais nanoestruturados
Oxidação
Oxido-hidróxidos mistos de Ni/Ce
Abstract in Portuguese
Nesta dissertação, novos nanomateriais à base de hidróxido de níquel aditivados com cério (Nix(OH)2x-Ce1-x, onde x = 0,8; 0,95 e 1) foram preparados e suportados em FTO gerando eletrodos modificados do tipo Nix(OH)2x-Ce1-x/FTO. Tais materiais foram obtidos pelo método sol-gel e caracterizados pelas técnicas de microscopia eletrônica de varredura e de transmissão (SEM e TEM), análise elementar por ICP-OES, espectroscopia fotoeletrônica de raios X (XPS), difratometria de raios-X (XRD) e voltametria cíclica (CV). Os resultados foram consistentes com a fase α-Ni(OH)2 para todos os nanomateriais. Os resultados revelaram também que o eletrodo α-Ni(OH)2-Ce(20)/FTO apresentou atividade eletrocatalítica aumentada para oxidação de metanol e glicerol frente ao α-Ni(OH)2 e α-Ni(OH)2-Ce(5), sugerindo um possível efeito sinérgico devido a formação de Ce(IV), mas após 3 dias verificou-se o aparecimento de uma nova fase menos ativa. Acredita-se que o processo de preparação e a composição podem ser otimizados para gerar materiais mais estáveis e minimizar tal processo, aumentando as perspectivas de aplicações para o desenvolvimento de dispositivos eletroquímicos como as células a combustível.
Title in English
Nanostructured mixed alfa-Ni/Ce hydroxide as electrocatalyst for oxidation of alcohols
Keywords in English
Alcohols
Electrocatalysis
Fuel cells
Nanoparticles
Ni/Ce mixed oxi-hydroxides
Oxidation
Abstract in English
In this work, new nanomaterials based on nickel hydroxide additivated with cerium(III) were prepared and supported on fluorine doped tin Oxide (FTO) (Nix(OH)2x-Ce1-x/FTO), x= 0,8; 0,95 e 1. Such materials were obtained by sol-gel method and characterized by scanning and transmission electron microscopy (SEM and TEM), elemental analyses by (ICP-OES), X-ray photoelectron spectroscopy (XPS), X-ray diffractometry (XRD) and cyclic voltammetry (CV) techniques. The results were consistent with the -Ni(OH)2 phase in all nanomaterials. The results revealed also that the α-Ni(OH)2-Ce(20)/FTO electrode exhibited an enhanced electrocatalytic activity towards oxidation of methanol and glycerol than α-Ni(OH)2 and α-Ni(OH)2-Ce(5) but the appearance of a new phase with lower electrocatalytic properties was verified after 3 days. We believed that the preparation process and the composition can be optimized in order to generate stable materials thus overcoming that drawback, increasing the perspectives for the development of electrochemical devices such as sensors and fuel cells.
 
WARNING - Viewing this document is conditioned on your acceptance of the following terms of use:
This document is only for private use for research and teaching activities. Reproduction for commercial use is forbidden. This rights cover the whole data about this document as well as its contents. Any uses or copies of this document in whole or in part must include the author's name.
Publishing Date
2019-05-06
 
WARNING: Learn what derived works are clicking here.
All rights of the thesis/dissertation are from the authors
CeTI-SC/STI
Digital Library of Theses and Dissertations of USP. Copyright © 2001-2021. All rights reserved.