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.
