Synthesis of nickel oxide/hydroxides and their nanocomposites with carbon materials for supercapacitor and gas sensing applications

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dc.contributor.advisor Manyala, Ncholu I.
dc.contributor.coadvisor Mwakikunga, Bonex W.
dc.contributor.postgraduate Khaleed, Abubakar Abubakar
dc.date.accessioned 2017-11-23T07:37:59Z
dc.date.available 2017-11-23T07:37:59Z
dc.date.created 2017
dc.date.issued 2017
dc.description Thesis (PhD)--University of Pretoria, 2017. en_ZA
dc.description.abstract The goal of this thesis is to produce NiO- and Ni(OH)2-carbon based nanocomposites and explore their possible adoption as active electrode materials in supercapacitor and gas sensing applications. Field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray powder diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and gas adsorption analyses were utilized to evaluate the structure and morphology of all samples in this study. The major aim of integrating carbon-based nanomaterials (graphene foam, graphene oxide and activated carbon) into Ni-based oxides and hydroxides in this study is to take advantage of their outstanding characteristics. These include good electrical conductivity, high corrosion resistance, large SSA, low-cost, good cyclic and temperature stability, as well as the capability to serve as a substrate for growth of other materials to form a suitable composite. The electrochemical evaluation as a potential supercapacitor electrode was employed in a three (3)-electrode configuration for the as-prepared Ni(OH)2/carbon based electrodes (NiOH)2/graphene foam and Ni(OH)2/graphene oxide electrodes) while the gas sensing characteristics of NiO/carbon-based electrodes were investigated using NCSM-CSIR gas sensing station controlled by a KEITHLEY pico-ammeter system. The electrochemical results of Ni(OH)2/carbon-based electrodes have demonstrated a superior electrochemical performance as compared to the pristine Ni(OH)2 electrodes with the results comparable and even better than some earlier related studies available in the literature. Similarly, NiO/carbonbased electrodes in the form of NiO/graphene foam and NiO/activated carbon electrodes both exhibited enhanced gas sensing properties in comparison to the pristine NiO electrode due to the increased specific surface area and electrical conductivity that are linked to its sensing response, response time and recovery time. Thus, the results obtained from these studies have clearly established the viability of these carbon-based nanomaterial composites as promising candidates for electrochemical supercapacitor and gas sensing applications. en_ZA
dc.description.availability Unrestricted en_ZA
dc.description.degree PhD en_ZA
dc.description.department Physics en_ZA
dc.description.sponsorship CSIR-National Centre for Nano-Structured Materials en_ZA
dc.description.sponsorship South African national research foundation (NRF) en_ZA
dc.identifier.citation Khaleed, AA 2017, Synthesis of nickel oxide/hydroxides and their nanocomposites with carbon materials for supercapacitor and gas sensing applications, PhD Thesis, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/63307> en_ZA
dc.identifier.other S2017 en_ZA
dc.identifier.uri http://hdl.handle.net/2263/63307
dc.language.iso en en_ZA
dc.publisher University of Pretoria
dc.rights © 2017 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.
dc.subject UCTD en_ZA
dc.title Synthesis of nickel oxide/hydroxides and their nanocomposites with carbon materials for supercapacitor and gas sensing applications en_ZA
dc.type Thesis en_ZA


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