Papers by Dr Fabian Ezema
Current Opinion in Electrochemistry
Thin Films
Nanoparticles are small particles that range from 1 to 100 nm in size, exhibit several physical a... more Nanoparticles are small particles that range from 1 to 100 nm in size, exhibit several physical and chemical features. An understanding of nanoparticles would reveal great qualities and potential applications that would aid the diversification of thin film technologies. The synthesis methods employed like top-down, bottom-up, chemical, biological, and mechanical processes have great influence on the properties exhibited by such nanomaterials. This review covers an insight into the knowledge of nanoparticles, their classifications, parameters affecting their efficient performance, synthesis and characterization techniques of nanoparticles. Nanoparticles are also characterized to obtain their morphological, structural, optical, elemental, size, and physiochemical features. The potential applications of nanoparticles have not been left undiscussed.
SSRN Electronic Journal, 2022
IOP Conference Series: Earth and Environmental Science, 2021
ZnO nanoparticles were synthesized via low temperature hydrothermal synthesis procedures at 90 °C... more ZnO nanoparticles were synthesized via low temperature hydrothermal synthesis procedures at 90 °C using zinc nitrate hexahydrate as the zinc oxide precursors and hexamethyleneamine as the precipitating agent. The structural, surface morphology and optical studies of the hydrothermally synthesized ZnO nanoparticles revealed that the synthesized products were nano-rods, grown in very high-density with well-crystalline wurtzite hexagonal phase and good optical properties. Ployvinyl alcohol (PVA) was used as surfactant to modify the surface features of the ZnO nanorods. The ZnO nano-rods were employed as photo-anode for dye sensitized solar cell (DSSC) and were sensitized by natural dye extracted from Baphia nitida plant. The photovoltaic characteristics of the cell such as the short circuit current, open circuit voltage as well as the shunt and series resistances of the cell were studied. The incident photon to current conversion efficiency was also studied. The study revealed that the...
Materials Today: Proceedings, 2021
In this study, we synthesized silver nanoparticles (AgNPs) using environmentally benign capping a... more In this study, we synthesized silver nanoparticles (AgNPs) using environmentally benign capping agents Telfairia occidentalis (TO) which reduced silver ions to AgNPs without any external reducing agent. The synthesized AgNPs were characterized by scanning electron microscope (SEM), X-ray dispersive spectroscopy (XRD), UV-Visible spectroscopy and Fourier transforms infrared spectroscopy (FT-IR) analysis. The SEM analysis gave a spherical morphology with particle size ranged between 15.84 and 19.2 nm with some hollow sphere microstructure of AgO-NPs which makes it suitable for biomedical applications. The XRD spectrum showed Fcc crystalline structure of AgO-NPs of intense peaks and average particle size of 8 nm and 10 nm for sample a and b respectively. The UV-Visible confirm the formation of AgO-NPs with surface plasmon resonance (SPR) absorbance peak of 327 nm. The antibacterial activities of AgO-NPs were found to be effective against human pathogens K. Pneumonia and could be successfully used as malarial therapeutic tools.
JCIS Open, 2021
Abstract There has been an increasing number of studies in magnetic nanoparticles with auspicious... more Abstract There has been an increasing number of studies in magnetic nanoparticles with auspicious applications in medicine. Among the oxides of magnetic nanoparticles, iron oxide has emerged as an indispensable tool in nanotechnology, particularly bio-nanotechnology. This is attributed to its exceptional properties such as size, shape, magnetism, and biocompatibility. In this review, iron oxide nanoparticles were exploited in different model organisms ranging from prokaryotes to eukaryotes, elucidating their cellular functions relative to their antibacterial activity, drug delivery, and toxicity.
Current Research in Green and Sustainable Chemistry, 2021
Abstract We show in this article the possibilities of employing an environmentally friendly, unco... more Abstract We show in this article the possibilities of employing an environmentally friendly, uncomplicated, economical and sustainable green synthesis technique effected by natural extracts from waste maize (zea mays lea) materials to synthesize some functional transition single metal oxide nanoparticles (NPs). Copper oxides (Cu2O and CuO), zinc oxide (ZnO), nickel oxide (NiO), chromium oxide (Cr2O3), iron oxide (Fe2O3) and cadmium oxide (CdO) were successfully synthesized using this facile method. Structural characterizations by X-ray diffraction (XRD) for the various oxides show the phases and space groups corresponding to their individual structures. Images from the high resolution transmission electron microscope (HRTEM) revealed various shapes and sizes of the obtained nanoparticles. Results from the attenuated total reflection-Fourier transform infrared (ATR-FTIR) revealed different kinds of functional groups present in the synthesized metal oxide nanoparticles. We showed that the phytochemicals in the natural extracts obtained from the waste materials from Zea mays lea plant is pivotal to the bio-reduction, stabilization and chelation of the metal oxide nanoparticles.
Journal of Nanoparticle Research, 2021
A biogenic protocol has been adopted for the formulation of zinc ferrite nanoparticles (ZFNPs) us... more A biogenic protocol has been adopted for the formulation of zinc ferrite nanoparticles (ZFNPs) using an aqueous extract of Allium cepa (AC) as a reducing agent for the optimization of its properties. The various characterization results from XRD, SEM, DRS, Raman, and VSM clearly showed that the formulated ZFNP was a single phase with crystallite size in the range of 11–15 nm. A spherical morphology was observed for all the samples with particle size in the range of 34–52 nm. All the samples showed a superparamagnetic behavior with reduced saturation magnetization. The ZFNPs prepared were used for self-heating analysis in hyperthermia applications at 180 Oe applied field and 425 Hz. It produced enough heating within the therapeutic temperature to attain the Curie temperature. The ZFNP formulated is auspicious for hyperthermia applications with less side effect owing to their biocompatibility, moderate Curie temperature, and SAR value within the therapeutic range. The formulated nanoparticles have further broadened the horizon of hyperthermia therapeutic applications with an innocuous protocol within 300 s.
Surfaces and Interfaces, 2021
In-situ biosynthesis of silver nanoparticles for antibacterial activities doped with aqueous extr... more In-situ biosynthesis of silver nanoparticles for antibacterial activities doped with aqueous extract of dry Gongronema Latifolium (DGL) is presented in this work. The absorbance was determined using a UV-Visible analysis with a peak of 428 nm. The obtained particles confirmed by the TEM image analysis were spherical in shape with an average particle size between 5 and 20 nm. A single crystalline phase of FCC was confirmed by the powder. The functional groups showed the phytochemical inherent in the sample. The colloidal solution of DGL-AgNPs with MIC of 10 µg/ml showed a noteworthy functional susceptibility against the bacterial strains, particularly, K. pneumonia with susceptibility greater than gentamicin. Based on these observations, the formulated DGL-AgNPs show strong bactericidal against the pathogens with facile, benign, eco-friendly, biocompatibility and innocuous synthesis procedures. This can serve as an efficient bactericidal agent.
Journal of Nanoparticle Research, 2020
We successfully synthesized CuFeS 2 nanoparticles (NPs) using a simple synthesis method mediated ... more We successfully synthesized CuFeS 2 nanoparticles (NPs) using a simple synthesis method mediated by touch me not (Mimosa pudica) leaves extract. Xray diffraction (XRD) was used to analyze the structural properties, and it shows that the CuFeS 2 NPs have a tetragonal structure and quasi-pyramidal NPs of an average crystallite size of 31.0 nm with a secondary phase of few minor peaks of covellite (CuS). The optical characterization showed that CuFeS2 NPs have band gap energy ranges of 1.98-2.46 eV for different annealing temperatures. The electrochemical properties of the CuFeS 2 NPs were investigated using cyclic voltammetry (CV), galvanostatic charge discharge (GCD), and electrochemical impedance spectroscopy (EIS). An appreciable value of specific capacitance of 501.4 F/g was obtained at a scan rate of 10 mV/s for the CuFeS 2 NPs annealed at 250°C which can be said to be within the optimum ideal annealing temperature for CuFeS 2 NPs. The CuFeS 2 NPs was used in the photodegradation of methylene blue (MB) under of solar irradiation. The highest rate constant of 3.1 × 10 −2 min −1 and degradation efficiency of 98% were obtained for the unannealed CuFeS 2 NPs with good stability after three cycles. Therefore, the synthesized
Journal of Alloys and Compounds, 2020
We synthesized NiO nanoparticles (NPs) using a simple, cost effective, eco-friendly and sustainab... more We synthesized NiO nanoparticles (NPs) using a simple, cost effective, eco-friendly and sustainable green synthesis route mediated by maize (Zea mays L.) dry silk extract. Structural characterizations by X-ray diffraction (XRD) and higher resolution transmission electron microscope (HRTEM) show that the NiO NPs have a cubic (fcc) structure (space group: Fm3m) with spherical and quasi spherical NPs of average diameter of 10e20 nm. The supercabattery properties of the NiO NPs were studied using cyclic voltammetry (CV), galvanostatic charge discharge (GCD) cycles and electrochemical impedance spectroscopy (EIS). A capacity of 54C g À1 was obtained a scan rate of 5 mV s À1 and capacity retention of 60% after 2000 GCD cycles. Asymmetric supercabattery devices were developed using activated carbon and NiO NPs as the negative and positive electrode respectively. The device with positive electrode to negative electrode mass ratio of 1:1 gave superior electrochemical energy storage capabilities compared to others giving a specific capacity of 29C g À1 at a specific current of 0.25 A g À1. Therefore, the synthesized NiO NPs obtained using Zea mays lea silk aqueous extract have potential application in electrochemical energy storage devices.
Inorganic Chemistry Communications, 2020
Successful synthesis of TiO2 nanoparticles at 300 o C, 500 o C and 600 o C by SILAR method. TiO2 ... more Successful synthesis of TiO2 nanoparticles at 300 o C, 500 o C and 600 o C by SILAR method. TiO2 nanoparticles synthesized at brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by University of Johannesburg Institutional Reposito Nanospherical balls with an average grain size of about 31 nm were exhibited by the anatase and rutile phases of TiO2 crystal structure. TEM and SAED patterns showed agglomerations of nanospherical balls with Debye Scherrer's rings which correspond to the crystal lattice planes of TiO2 while the elemental presence of the deposited nanoparticles were confirmed from the EDX studies. High transmittance percentage with optical band gap energy ranging from 3.41-3.60 eV was obtained. The chemical vibrational bonds existing between the nanoparticles and the band-to-band transitions and were evident from the FTIR and PL studies respectively.
Physica B: Condensed Matter, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Materials Chemistry and Physics, 2019
Biosynthesis of AgNPs via aqueous extracts of GL was demonstrated for the first time. � Fresh lea... more Biosynthesis of AgNPs via aqueous extracts of GL was demonstrated for the first time. � Fresh leave of Gongronema Latifolium serves as a substitute to chemical reagents. � GL phytochemicals worked as a fuel that reduced Ag ion to AgNPs. � AgNPs show strong bactericidal against Coliform, E. Coli and S. aureus. � AgNPs exhibit higher inhibition zone against the bacterial cells compared to standard drug.
Physica B: Condensed Matter, 2019
This work demonstrated an in-depth investigation of the effect of surface doping by three differe... more This work demonstrated an in-depth investigation of the effect of surface doping by three different polymers on the synthesis of zinc ferrite nanostructures by a thermal method. The zinc ferrites were doped with 20 % concentration by mass of Polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP) and Polyethylene glycol (PEG) to enhance its properties. The X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) confirmed the incorporation of the polymers in the lattice with an obvious increase in the crystallite size, functional groups, spherical morphology, and superparamagnetic behavior respectively. It is noteworthy that the cubic crystalline structure, favorable particle size and magnetic properties of the doped samples gave the NPs a controllable and improved properties for sundry applications in the medical fields such as Hyperthermia and drug delivery with PEG dopant showing a towering leverage on the properties of the ZF with 11 % polydispersity Index (PDI).
Arabian Journal of Chemistry, 2018
The effect of 5 MeV Cu ++ ions irradiation on structural and optical properties of Anatase TiO 2 ... more The effect of 5 MeV Cu ++ ions irradiation on structural and optical properties of Anatase TiO 2 nanoparticles (TiO 2-NPs) is investigated. For this purpose, TiO 2-NPs are irradiated with different Cu ++ ions fluences, ranging from 1 Â 10 15 to 1 Â 10 16 ions/cm 2 at room temperature. XRD results confirm the Ti 3 O 7 phase appear at the dose of 5 Â 10 15 ions/cm 2 and peak intensity of Ti 3 O 7 phase gradually increases with an increase of Cu ++ ions irradiation dose. At the dose of 1 Â 10 16 ions/cm 2 TiO 2 Anatase phase were transformed to Rutile phase. Same observations are confirmed from Raman spectroscopy. High resolution transmission electron microscopy
ISRN Nanomaterials, 2012
We report the synthesis of various shaped silver nanoparticles mediated by ZnCl2 salt. It has bee... more We report the synthesis of various shaped silver nanoparticles mediated by ZnCl2 salt. It has been demonstrated that the salt, PVP/AgNO3 mole ratio, and the type of polyol (EG, DEG,and GL) significantly determined twinning probability, which is an index of silver seed growth origin. High twining probability arising from low PVP/Ag+ ratio and 50 mole% salt favours 1D grown nanowires and nanorods, whereas low twining amidst high mole% salt (150) in DEG offered 2D grown nanoflakes and nanosheets. Other shaped silver nanoparticles have been found. Accidentally, we arrived at a core-shell heterostructure of Ag-ZnO nanocomposite with Ag core enrichment when mole% of the salt was made up to 300. Growth kinetic of nanosphere obtained was monitored, and effect of salt mediation was found crucial. Structural evolution of shaped Ag nanoparticles and nanocomposites have been monitored using XRD, SEM, EDX, TEM, and UV/vis.
Uploads
Papers by Dr Fabian Ezema