Mohammed Khenfouch

University of South Africa | unisa · Department of Physics

The importance of green process in the synthesis of nanomaterials becomes universally known. In this study, we report on the efficiency of a Aspalathus linearis’s plant extract known as Rooibos tea on the synthesis of graphene via a bio-active process. Using several nanocharcterization techniques, our investigations on the main physico-chemical pro...

The proposed work focuses on the effects of growth time and annealing on the physico-chemical performance of vanadium oxides nanostructures (VO-NSs) films synthesized by a novel single reaction microwave synthesis. Thin films of VO-NSs were produced on glass substrates by varying the growth time and annealing temperature. Structural studies reveale...

Density functional theory-based investigation of the electronic, magnetic, and optical characteristics in pure and ytterbium (Yb) doped ZnO has been carried out by the plane-wave pseudopotential technique with generalized gradient approximation. The calculated lattice parameters and band gap of pure ZnO are in good agreement with the experimental r...

Yb doped ZnO nanorods were prepared on glass substrates by the hydrothermal method in order to investigate the insertion of Yb ions in the ZnO matrix and the related morphological, structural and vibrational properties of the samples. X-ray diffraction patterns showed that the undoped and Yb doped ZnO nanorods exhibit the hexagonal wurtzite crystal...

ZnO nanorods combined with different concentrations of reduced graphene oxide were synthesized using the hydrothermal method. Structural properties of these nanocomposites were studied by X-ray diffraction analysis. Morphological studies on the shape and size of nanorods were carried out by scanning electron microscopy. X-ray diffraction results re...

We report the magnetic properties of Ba0.99Sm0.01TiO3 (BSmT1) sample synthesized through the sol–gel process. The sample consisted of crystallites of nanometric sizes (33.2 nm). The magnetization was measured at different temperatures and different magnetic applied fields using the vibrating-sample magnetometer (VSM) technique. The curves of magnet...

In this paper, we have calculated the optical properties of the different polytypes of GaSe lamellar materials. The calculations are based on the DFT method and is performed using the CASTEP code. All optical properties have been studied in a domain that extends energetically from 10 meV to 35eV and have been measured for a polarization // and ⊥ wi...

In this work, the effects of graphene oxide (GO) concentrations (1.5 wt.%, 2.5 wt.%, and 5 wt.%) on the structural, morphological, optical, and luminescence properties of zinc oxide nanorods (ZnO NRs)/GO nanocomposites, synthesized by a facile hydrothermal process, were investigated. X-ray diffraction (XRD) patterns of NRs revealed the hexagonal wu...

This contribution reports on the optical properties of biosynthesised ${\rm{Eu}_2}{{\rm{O}}_3}$ E u 2 O 3 nanoparticles bioengineered for the first time by a green and cost effective method using aqueous fruit extracts of Hyphaene thebaica as an effective chelating and capping agent. The morphological, structural, and optical properties of the samp...

We report on the synthesis and enhanced thermal conductivity of stable Ag-decorated 2-D graphene nanocomposite in ethylene glycol based nanofluid by laser liquid solid interaction. A surfactant free nanofluid of Ag nanoparticles anchored onto the 2-D graphene sheets were synthesized using a two-step laser liquid solid interaction approach. In order...

In this work, ZnO nanorods were synthesized by a simple and low-temperature hydrothermal method. Their surfaces were coated by Holmium using the drop-coating deposition technique. The morphology and the structural measurements showed that Holmium has coated completely the surface of ZnO; nanorods have hexagonal structure and their average diameter...

In this paper, the influence of graphene oxide coating on optical and photoluminescence properties of zinc oxide nanorods (ZnO NRs) has been investigated. ZnO NRs were prepared using a hydrothermal route (from zinc nitrate hexahydrate and hexamethylenetetramine), graphene oxide (GO) was fabricated by Hummer's method, while for synthesis of ZnO nano...

Zinc Oxide (ZnO) thin-films were grown on glass substrate using chemical bath deposition method (CBD) from precursors containing varying molar concentrations of zinc acetate. The structure, morphology, optical and luminescence properties of the films were investigated using X-ray diffraction (XRD), Scanning electron microscopy (SEM), Ultraviolet vi...

In this paper, we have studied the influence of the temperature on the diamagnetic susceptibility of a shallow donor confined to move in a quantum box (QB) made out of GaAs/Ga1−xAlxAs with a uniform magnetic field. The Hass variational method within the effective mass approximation is used in the case of finite barrier confining potential. In the c...

In this work, the effect of the temperature on the binding energy and the diamagnetic susceptibility of a shallow magneto-donor confined to move in a cylindrical quantum dot made out of GaAs/GaAlAs is studied within the effective mass approximation. We describe the quantum confinement by an infinite deep potential. The results show that when the te...

Vanadium dioxide (VO 2 ) have attracted tremendous interest in recent years due to their semiconductor-metal transition near room temperature. In this work, we report numerical simulation of the optical properties of VO 2 thin layers which include the index of refraction, the coefficient of extinction, the reflectance and the transmittance. In this...

Nowdays, nanocomposites containing ZnO with various morphologies and graphene, graphene oxide (GO) or reduced graphene oxide (rGO) have been attracting many researchers according to their properties and board application in optoelectronic devices. In this study, rGO/ZnO nanorods were synthesized using different procedures. In the first procedure, Z...

Graphene oxide (GO) decorated with nanostructured porphyrin (PN) was synthesized and the interfacial interaction between these two components were investigated by using Scanning electron microscopy (SEM), X-ray, and UV-Visible absorption spectroscopy. These techniques showed good dispersion of GO and PN as well as a π-π intermolecular interaction c...

We have studied the magnetic field effects on the diamagnetic susceptibility and binding energy of a hydrogenic impurity in a Inhomogeneous Quantum Dots by taking into account various geometries of these systems like spherical, cylindrical and cubic inhomogeneous Quantum Dots. The calculation was performed with the use of a variational method in th...

Rare earth Er-doped ZnO nanorods were prepared by a simple hydrothermal method in order to search for a new functional for potential application in optoelectronic. Nanorods were deposited onto glass substrates with zinc nitrate, hexamethylenetetramine and Erbium chloride as starting materials. The results obtained by XRD spectrum indicated the pres...

We investigated the effect of the hydrostatic pressure on the optoelectronic properties of a quantum well (QW) based on δ -doped GaAs sandwiched by Ga 1- x Al x As. We study the case of a non-parabolic conduction band where the aluminum content is set at 30%. We perform our calculations in the context of the approximation of the envelope function f...

In this paper, we present the structural and optical properties of Graphene oxide/ZnO nanorods/graphene oxide (GO/ZnO nanorods/GO) nanocomposites prepared via a hydrothermal method on Si (100) substrate. The X-ray diffraction measurements (XRD) confirm that the prepared samples are of hexagonal wurtzite structure with crystallite size around 50–60...

Sol–gel route was used to prepare Fe-doped CdTiO3 sample with 1 wt% and its optical and magnetic properties investigated. In particular, photoluminescence study revealed the existence of defects, such as oxygen vacancies, and of transitions from electronic states of Cd²⁺, Ti⁴⁺ and Fe²⁺ to those of O²⁻. Magnetic investigations showed the existence o...

Recently, ZnO Nanostructures have attracted considerable attention due to their various morphologies, easy synthesis and excellent physical properties for fabricating optoelectronic devices. In this study, we report the synthesis of Yb doped ZnO nanorods via a green process using plant extracts. Their morphology, structural and optical properties w...

The emerging field of organic/inorganic nanocomposites has become the focus of considerable research in recent years. In particular, graphene coated with iron oxide nanostructures are widely required for various applications. In this work, we report the preparation of graphene oxide/magnetite GO/Fe3O4 nanocomposite via a simple hydrothermal method....

Zinc oxide (ZnO) is a very promising material for optoelectronic applications thanks to its wide direct band gap (3.4 eV), and a high exciton binding energy (60 meV). ZnO based nanostructures are presently being explored for a wide range of applications in nanolasers, nanogenerators, gas sensors, light emitting diodes and solar cells. In this study...

Nitrogen-doped graphene oxide (NGO) nanosheets were prepared via a facile one-pot modified Hummer's approach at low temperatures using graphite powder and flakes as starting materials in the presence of a nitrogen precursor. It was found that the morphology, structure, composition and surface chemistry of the NGO nanosheets depended on the nature o...

Transition metal oxides nanoparticles with different morphologies have attracted a lot of attention recently owning to their distinctive geometries, and demonstrated promising electrical properties for various applications. In this paper, we discuss the pH and annealing effects on the structural and electrical properties of vanadium oxides nanopart...

The present paper aims to study the mixing of reduced graphene oxide (RGO) with meso-tetrakis(4-phenylsulfonic-acid)porphyrin [H4TPPS42−] via a covalent functionalization, through a facile synthesis process. The intermolecular interaction was investigated using scanning electron microscope, Raman scattering, Fourier transform infrared spectroscopy,...

The influence of varying rotating magnetic field using a 2-pole three-phase induction motor on the removal of hexavalent chromium ions from wastewater using polypyrrole magnetic nanocomposite was explored in this study. Hexavalent chromium removal in this study was observed to be pH dependent under the influence of rotating magnetic field, as the p...

Graphene-ZnO nanostructures composite materials have been used as very efficient candidates for various optoelectronic applications. Nowadays, the composite structure formation of ZnO nanostructures with graphene or graphene oxide is a novel, cost effective and efficient approach to control the morphology, surface defect states, band gap of ZnO nan...

The graphene oxide functionalized Sn(V) tetrakis (4-pirydyl) porphyrin [SnTPyP²⁺] nanostructure, was prepared by simple method with multiple GO concentrations and different acidity levels. The vibrational properties were investigated by means of Raman scattering and FT- Infrared spectroscopies and showed that electronic interactions take place at t...

Polyethylene is the most commonly used plastic in daily life, covering wide areas of application e.g. this polymer is used as a greenhouses covering material. This article investigates the effect of photo-oxidation on commercial unstabilised Low Density Polyethylene (uLDPE), as result of outdoor weathering factors. In this study, the samples were e...

Herein, we present a comparative study between nanostructures of poly(3-hexylthiophene) (P3HT), Holmium-Graphene Oxide (HoGO) nanocomposite and hybrid HoGO/P3HT thin-film nanostructures in terms of structural morphological and spectroscopic properties. Specifically, the graphene based GO nanostructure was functionalized with rear earth ion Ho(III)...

One-dimensional ZnO nanostructures have been attracting growing research effort worldwide over the last few years due to their various morphologies, easy synthesis and excellent physical properties for fabricating optoelectronic devices. In this study, we have reported the synthesis of Holmium coated ZnO nanostructures. The structural, morphologica...

Nanostructured metal oxides have attracted a lot of attention recently owning to their unique structural advantages and demonstrated promising chemical and physical properties for various applications. In this study, we report the structural and electrical properties of vanadium dioxide VO2 (R) prepared via a single reaction microwave (SRC) synthes...

The efficiency of the nanophotocatalysts was determined in a laboratory prepared solutions of model dye compound methyl orange (MO), which is a dyestuff typically applied on textiles. The reduction in the concentration of the dye over time was measured by using UV-VIS spectrophotometry. The decolourisation of MO solutions was characterized at the o...

Composites of graphene oxide (GO) functionalized with Sn(V) tetrakis (4-pyridyl)porphyrin (SnTPyP2+) and meso-tetrakis(4-phenylsulfonic acid)porphyrin (H4TPPS 42−) were prepared at different pH values.Successful synthesis of water-soluble stable suspension of GO–SnTPyP2+ and GO–H4TPPS 42− was confirmed using various spectroscopic techniques, includ...

Studies on magnetic field exposure of congo red contaminated water employing polypyrrole magnetic nanocomposite is reported. Alternating magnetic poles as a function of time has been used to move functionalized nanoparticles in congo red contaminated water. A maximum removal of 94% was observed for the adsorption of 100 mg/L of the adsorbate using...

Among various graphene based materials, graphene-transition metal oxide nanoparticles have recently attracted tremendous research interest owning to their unique structural advantages, and demonstrated promising chemical and physical properties for various applications. In the present study, we discuss the pH effect on the structural, optical and e...

It is universally known that many polymers exhibit strong photoluminescence in the UV–Visible and near infrared range. In addition, zinc oxide (ZnO) is well knows as a promising strong luminescent material. In this sense, this work reports on the preparation and characterization of nanofibers based on zinc oxide nanorods embedding polyvinyl alcohol...

Functionalized graphene oxide have received much attention in a broad range of applications from light harvesting.The interactions between graphene and Meso-tetrakis(4-phenylsulfonica-acid)porphyrin (H4TPPS4²⁻), especially π-π interactions have also been extensively investigated. The composite material formed stable dispersions was characterized by...

Nanostructured metal oxides have attracted a lot of attention recently owning to their unique structural advantages, and demonstrated promising chemical and physical properties for various applications. In this study, we report the structural and optical properties of vanadium oxide nanoparticles (VO-NPs) prepared via a hydrothermal method. Our res...

Silver nanoparticles (AgNPs) grown on a three dimensional (3d) graphene networks (GNs) has been successfully prepared by an efficient and rapid microwave-assisted growth process to form GNs/AgNPs nanocomposite electrode materials for supercapacitor application. The 3d nature of the used GNs offers a unique architecture, which creates an efficient c...

Graphene derivatives attracted tremendous attention world-wide owing to their promising properties and potential applications and interest in studying the photoluminescence quenching in nanomaterials has constantly been on the increase in recent years. In this sense, the current study provides an investigation of this optical phenomenon in graphene...

Graphene oxide (FGO) decorated with nanostructured porphyrin (PN) was synthesized and the interfacial interaction between these two components were investigated by using Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Raman scattering, Fourier transform infrared (FT-IR), X-ray, and Uv-visible. SEM and TEM showed good dis...

As the world demand for energy continue to increase, it is vital to improve renewable energy technologies that will replace conventional fossil fuels. Carbonaceous graphene oxide (GO) is a promising nanomaterial, easy to prepare and scale up to commensurate with industrial requirements. The nanocomposite was prepared in the form of layered structur...

Reduced graphene oxide has attracted great interest owing to its exceptional properties, and its combination with Porphyrins has many potential applications in optoelectronics, light emitting diodes and dye-sensitized solar cells, because of the long excited-state lifetimes and delocalizable electron density on the porphyrin. Few layers of reduced...

This contribution report is the 1st synthesis of nano-scaled Pd and PdO by a completely green process using Aspalathus linearis natural plant extract as an effective bio-reducing as well as a capping agent. Their spherical-like size was found to range within 〈Øparticles〉 = 3.8–22 nm. Their morphological, structural and optical properties were inves...

Nowadays graphene is universally known as a promising material. Hence, the development of eco-friendly synthesis methods for this material is of great importance. This study reports on the bio-synthesis of graphene by a green chemistry process using Artemisia herba-alba Asso (AHAA) natural extract. Moreover, this work reports on the physical proper...

The attractive optoelectronic properties of graphene are universally known. Also, their combination with polymer matrix added an exciting physical investigation. In the present work, nanocomposites based on poly (vinyl alcohol) (PVA) with low graphene oxide (GO) and partially reduced graphene oxide (PRGO) loadings (0.5, 1 and 2 wt%) were successful...

We report the structural, optical and electrical properties of Graphene-Vanadium oxide nanopar-ticles (rGO/VO-NPs) nanocomposites prepared via a hydrothermal method on glass substrates. The samples have been characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (ATR-FTIR), Raman sp...

Nanocomposites based on graphene oxide (GO)–iron oxide Fe3O4 and reduced GO (rGO)–Fe3O4 were synthesized by using a simple hydrothermal method, and their morphology and structure are investigated aiming to get an insight into on how the removal of oxygen group affects the dispersibility of Fe3O4 on GO layers. Transmission electron microscopy observ...

It is universally known that the preparation of high quality graphene on a large scale and in a cost-effective manner is essential for many technological applications. Graphene oxide (GO) has emerged as the precursor of choice for bulk production of graphene-based materials, as it can be synthesized from inexpensive graphite powders. In this paper,...

Nanocomposites based on few-layers graphene oxide (FGO) decorated with porphyrin nanorods (PN) were synthesized and the interfacial interaction between these two components was investigated by using scanning electron microscopy (SEM), photoluminescence spectro‐ scopy, resonant Raman scattering and Fourier transform infrared (FT-IR) techniques. SEM...