M. S. Dhlamini

University of South Africa | unisa · Department of Physics

This work investigates the potential of using Callistemon citrinu flower extract, commonly known as bottlebrush, in the environmentally friendly synthesis of Rhodium nanoparticles (Rh NPs). Callistemon citrinu flower extract contains a high concentration of flavonoids and other phytochemicals. Hence, the extract was used to provide the essential co...

The crucial role of In as a dopant on the structural, optical, and thermogravimetric characteristics of the zinc selenite (ZnSeO3) nanopowders has been investigated in detail using X-Ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Energy Dispersive Spectroscopy (EDS), Raman spectroscopy, diffuse reflectance spectroscopy...

Carbon materials (CMs) have extensively attracted widespread applications from the scientific communities because of their natural abundance, cost-effectiveness, large surface area, high conductivity, and simple functionalization route techniques. However, the agglomeration tendencies of most of the CMs due to their high Van der Wall force of attra...

BACKGROUND Marula (Sclerocarya birrea) is an indigenous African fruit‐bearing tree with many commercial uses; however, de‐kernelled seeds generated from marula fruit‐processing are wasted. The phytochemical constituents of de‐kernelled marula seeds have not been investigated previously and its extract/tea may potentially serve as a promising source...

ZnTiO3:Er3+,Yb3+ thin film phosphors were successfully deposited by pulsed laser deposition (PLD) at different substrate temperatures. The distribution of the ions in the films was investigated and the chemical analysis showed that the doping ions were homogeneously distributed in the thin films. The optical response of the phosphors revealed that...

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...

Doping ZnS nanoparticles with different metal and/or non-metal ions is one of the ways to improve their properties. That is because dopants introduce strain into the lattice of the ZnS nanoparticles. The influence of Ti on the ZnS nanoparticles was investigated on the structural properties, optical properties, and also electrical impedance spectros...

This work has investigated the effect of drying temperature on the crystallite size and lattice strain of NiCoAl-LDH using the Williamson–Hall (W–H) method and tracked the impact of the changes thereof on the electrochemical properties. During the experiments, the drying time was kept unchanged, while the temperature was varied from 70 °C, 80 °C to...

The electrode fabrication stage is a crucial step in the design of supercapacitors. The latter involves the binder generally for adhesive purposes. The binder is electrochemically dormant and has weak interactions, leading to isolating the active material and conductive additive and then compromising the electrochemical performance. Designing binde...

Titanium dioxide (TiO2) and holmium (1.2 mol% Ho³⁺) doped TiO2 nanoparticles were synthesized via sol-gel method using polyvinylpyrrolidone (PVP) co-polymer as a pore forming agent. The nanoparticles were dispersed in a solvent and drop-cast on a glass substrate to make films. The films were then calcined at 550 °C for 4 h in a pre-heated muffle fu...

The increasing environmental challenges such as the rise of global warming and depletion of fossil fuels have enthused the scientific community to dedicate tremendous effort to the development of various clean energy technologies in recent years [1-2]. Thus, most of the efficient, clean and sustainable energy production sources were successfully de...

A novel rare-earth free green-emitting Mn doped BaAl2O4 nanophosphor was prepared by combustion method. The crystal structure, morphology, phosphorescence, thermoluminescence and chemical composition were investigated. The XRD patterns confirmed the hexagonal BaAl2O4 phase and the existence of a small fraction of BaAl12O19 impurity phase. The SEM s...

Supercapacitors are promising energy storage devices that bridge the vent between batteries and conventional capacitors due to their outstanding properties. Their manufacture generally relies on the slurry casting process that aims to deposit onto a selected substrate the slurry which resulted from a mixture of active material, conductive additive,...

Perovskite materials activated with rare-earth ions have been found potentially attractive for photoluminescence applications. The luminescence characteristics of rare earth ions activated perovskite ZnTiO3 host lattice prepared by solid-state chemical reaction method is presented and discussed. The use of rare-earth ions in perovskite ZnTiO3 phosp...

Titanium dioxide (TiO2) nanoparticles were synthesized using sol-gel method and incorporated with co-polymers polyethylene glycol (PEG), polyvinylpyrrolidone (PVP) and pluronic F127 as pore forming agents. The samples were then calcined at 550 °C for 4 h to evaluate the effect of these co-polymers on the pore size and specific surface area. X-ray d...

A facile hydrothermal technique was employed to synthesized non-modulated cobalt-doped molybdenum sulfide (MoS2) nanoflowers. The as-prepared materials were coated on commercially available Ni-foam to fabricate electrode materials for supercapacitor applications. The elucidation of the structural information, surface morphology, microstructural pro...

The washing of layered double hydroxides (LDH) material is mostly purposed to discard the unreacted products after the reaction has been completed. However, this study demonstrated that the washing stage can also be targeted to optimise the electrochemical performance of LDH by using an appropriate solvent. Solvents, namely, ethanol, acetone, and a...

The fascinating features of 2D nanomaterials for various applications have prompted increasing research into single and few-layer metal dichalcogenides nanosheets using improved nanofabrication and characterization techniques. MoS2 has recently been intensively examined among layered metal dichalcogenides and other diverse transition metal-based ma...

The fascinating features of 2D nanomaterials for various applications have prompted increasing research into single and few-layer metal dichalcogenides nanosheets using improved nanofabrication and characterization techniques. MoS2 has recently been intensively examined among layered metal dichalcogenides and other diverse transition metal-based ma...

Energy is the driving force behind the upcoming industrial revolution, characterized by connected devices and objects that will be perpetually supplied with energy. Moreover, the global massive energy consumption increase requires appropriate measures, such as the development of novel and improved renewable energy technologies for connecting remote...

This study presents the simulations of a hybrid Cu2ZnSnS4-based solar cell with a planar heterojunction structure in a hybrid model (n-FTO/n-ZnO/p-PSCS/p-CZTS/p-PSCS/p-HTM) using a One-Dimensional Solar cell capacitance simulator (SCAPS-1D). The configuration "121" of the hybridizing absorber layers of the device was simulated and related with as-C...

This research work describes the synthesis of ZnO nanostructures doped with Ho3+ ions using a conventional sol–gel synthesis method. The nanostructured produced exhibited a wurtzite hexagonal structure in both ZnO and ZnO:Ho3+ (0.25, 0.5, 0.75 mol%) samples. The change in morphology with addition of Ho3+ dopants was observed, which was assigned to...

Molybdenum sulfide (MoS2) is one of the active materials used in the fabrication of two‐dimensional supercapacitors devices and has attracted increased attention because of its unique electronic properties with direct bandgap. The exposed active edge sites and large area‐specific surfaces present in MoS2 nanostructures are highly interesting proper...

Molybdenum sulfide (MoS2) is one of the active materials used in the fabrication of two‐dimensional supercapacitors devices and has attracted increased attention because of its unique electronic properties with direct bandgap. The exposed active edge sites and large area‐specific surfaces present in MoS2 nanostructures are highly interesting proper...

This work illustrates the sol-gel synthesis of dysprosium (Dy³⁺)-doped zinc silicate (Zn2SiO4) nanophosphor. The studies to evaluate its properties for possible application in solid state lighting and dosimetry were done. Synthesized nanophosphors were characterized using an X-ray diffraction (XRD) and field emission scanning electron microscopy (F...

The effect of Sr and Ag co-implantation and recovery annealing on the structural, mechanical and electrical properties of glassy carbon is reported. Glassy carbon was co-implanted with 200 keV Sr and Ag ions to a fluence of 1 × 10¹⁶ ions/cm² at room temperature. Combination of Raman spectroscopy and high resolution transmission electron microscopy...

The fluorescence vibrational features of as-synthesized P3HT–ZnO:Ho3+ and P3HT–ZnO:Tm3+ thin films were investigated using Gaussian analysis. Relative to P3HT–ZnO:Tm3+ film, detailed Gaussian analysis of the fluorescence spectra revealed weaker intensity exhibited in P3HT–ZnO:Ho3+ film due to better charge transfer. Moreover, we comparatively prese...

Molybdenum-based supercapacitors, a fast promising area where researchers are exploring the possibilities of improving the performance of its electrode materials and their derivatives for energy storage. Molybdenum sulfide (MoS2) has attracted considerable interest because of its superior properties as a supercapacitor-based material. In this mini-...

This paper reports the charge compensation effects of Al3+ incorporated ZnTiO3:Eu3+ as a codopant ion. The structural and morphological characterization show that the addition of Eu3+ and Al3+ does not affect the phase formation and the surface morphology of the host. There was an improvement in the luminescence emission intensity of Eu3+ ions for...

Pure zinc oxide NPs (ZnO NPs) have been synthesized using a simple eco-friendly approach using fruit extracts of Hyphaene thebaica. XRD pattern indicated zincite and highly crystalline phase of ZnO NPs. UV–Vis spectrum revealed surface plasmon resonance at 372 nm and bandgap of 3.36 eV. FTIR spectrum indicated characteristic Zn–O vibration at 450 c...

This contribution reports for the first time, the bio-synthesis of nanoscaled Copper oxide (CuO) nanoparticles via aqueous extract of Hyphaene thebaica as an effective chelating and capping agent. Their morphology and structural characterization of post annealing at 500 °C were confirmed by using X-Ray diffraction analysis (XRD) with average size 2...

The development of cost-effective and scalable synthetic methods is of paramount importance to achieve industrial application of energy conversion and storage devices based on layered double hydroxides (LDH). Herein, we synthesized NiCo-LDH nanosheets via a simple up-scalable co-precipitation method at relatively low temperature. Moreover, we used...

This contribution reports on the biosynthesis of the n-type Bismuth vanadate (BiVO4) nanorods prepared via the use of aqueous extracts of Callistemon viminalis as an effective chelating agent. To ascertain the formation of crystalline and pure BiVO4 nanorods, various surface & interface characterization were performed on annealed BiVO4 powders. X-R...

This paper aimed to study the influence of zirconium phosphate (ZrP) nanoparticles on reducing the diameter of nanofibres during electrospinning. Addition of metal oxide such as zirconium phosphate decreases the diameter and smooths on the polyacrylonitrile (PAN) nanofibres as observed by the SEM techniques. Furthermore, this work investigated the...

Stable and high surface area zirconium oxide nanoparticles have been synthesised by means of the hydrothermal method. The Brunauer–Emmett–Teller results show that a high surface area of 543 m²/g was obtained in the hydrothermal process, having a high porosity in nanometre range. The hydrothermal method was applied at 120 °C by using an autoclave wi...

The synthesis temperature of zirconium oxide nanoparticles was varied during the reaction in order to observe its influence on the crystallinity and particle size of zirconium oxide particles. Zirconium oxide synthesized by the precipitation method resulted in relatively small particle size with small distance between the lattice fringes (0.2928 nm...

α-Fe2O3 and α-Fe2O3:Er³⁺ nanoparticles at different concentrations have been successfully synthesized by microwave synthwave method. The XRD confirmed the hexagonal structure of α-Fe2O3 pure phase and no impurities were present confirming the substitution of Fe³⁺ with Er³⁺. The UV–Vis show the absorption band from the Er³⁺ assigned to ⁴I11/2 and th...

The effect of annealing on the diffusion of silver, silver and strontium co-implanted in glassy carbon was investigated. Glassy carbon samples were implanted with 360 keV Ag ions at room temperature. The RBS profile showed that Fickian diffusion of Ag in glassy carbon is only observed at temperatures ranging from 500 °C–600 °C. At higher annealing...

Zirconium phosphates (ZrP) were incorporated into Nafion® 117 membrane by impregnating method to obtain a reduced methanol permeation and improved proton conductivity for fuel cell application. The mechanical properties and water uptake of Nafion® membrane incorporated with zirconium phosphates nanoparticles was more improvement when compared to th...

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...

Membranes are widely used daily, such as for filtration in reverse osmosis, or in the form of electrolyte membrane fuel cells. Modified Nafion® membranes were synthesised by impregnation and their mechanical properties were observed. The effect of the incorporation of a ZrO2-CNT nano-filler within Nafion® membrane on the thermal stability and cryst...

Nafion®/sulfated zirconium nanocomposite membranes were prepared by incorporating sulfonated zirconia with ammonia sulfate and sulphuric acid, which enhances proton conductivity and reduces fuel crossover on Nafion® membrane as they sustain water affinity and strong acidity. XRD, AFM, SEM, FTIR and TGA were used to investigate the morphology and hi...

Stimulated luminescence of novel La 2 O 3 nanophosphors doped with Dy 3+ and Eu 3+ and co-activated with Li + , prepared by microwave-assisted solution combustion synthesis, was investigated for the very first time. X-ray diffraction results indicated hexagonal La 2 O 3 crystalline phase. Lanthanide and Li + doping did not affect the La 2 O 3 cryst...

The present paper reports on down-and up-conversion luminescence behaviour of sol-gel derived erbium doped titanium dioxide with anatase structure. Through combined structural, optical and electron microscope analysis, effective and influence of Er³⁺ doping into TiO2 lattice has been demonstrated using X-Ray diffraction (XRD), scanning electron mic...

This work investigates the structural and optical properties of SrAl2O4: 2%Mn²⁺ and BaAl2O4: 2%Mn²⁺ nano-phosphors. These nano-phosphors were synthesized by a conventional combustion method at 600 °C, using urea as a fuel. The effects of crystal lattice sites, hence the crystals field on the electronic transitions of Mn²⁺ have been investigated. Th...

Ab initio density functional theory calculations were employed to investigate the effect of Tm, Ho and Er substitutional dopants on the electronic and optical properties of Yb activated hexagonal zinc titanate (Yb:ZnTiO3). The Zn site was found to be the energetically favoured substitutional dopant site both for Yb activation and also Tm, Ho and Er...

In this contribution we report on the synthesis of n-type Bismuth vanadate (BiVO 4 ) nanorods prepared via the use of aqueous extracts of Callistemon viminalis. X-ray diffraction analysis confirmed the formation of highly crystalline monoclinic BiVO 4 nanorods post annealing of the Bismuth vanadate precursor powder at 500 °C. Scanning Electron Micr...

Nowadays, the development of efficient green chemistry methods for synthesis of metal oxides nanoparticles has become a major focus of researchers. These methods are being investigated in order to find an eco-friendly technique for production of well-characterized nanoparticles. In this contribution we report for the first time, the synthesis and s...

Transparent conductive aluminum-doped zinc oxide (AZO) thin films were deposited on a flat and nanostructured borosilicate glass substrates by using DC-magnetron sputtering. The aluminum doping concentration was kept at 3.3 wt% and the film thickness (100–400 nm) was varied. The thin films were then annealed at 250 °C for 1 h in nitrogen and/or arg...

Recycling of domestic and agricultural organic waste is a fresh and exciting concept which promises both economic growth and environmental benefits. The production of organic waste continues on a daily basis, from domestic food, animal waste and dead animals. They all pollute the environment and may harm the people. The South African government has...

The Williamson-Hall (W-H) equation, which has been used to obtain relative crystallite sizes and strains between samples since 1962, is revisited. A modified W-H equation is derived which takes into account the Scherrer equation, first published in 1918, (which traditionally gives more absolute crystallite size prediction) and strain prediction fro...

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)...

The electrical conduction mechanisms were investigated for the CdS and Cu-doped CdS (CdS:Cu) nanoparticles embedded in polyvinyl alcohol (PVA) (PVA/CdS and PVA/CdS:Cu) nanocomposites; synthesized by the chemical Sol Gel method on indium tin-oxide (ITO) substrate. X-ray diffraction pattern results show that the PVA/CdS nanocomposite is hawleyite-stu...

With increasing awareness of protecting the environment, the demand for renewable and environmental materials is increasing. In this work, the cellulose single fibers (CSFs) were extracted from the African native Napier grass fibers (NGFs) by chemical process. NGFs and CSFs were characterized for their chemical composition, structure, morphology, c...

The mechanical stability of modified membranes has become a priority for fuel cell applications as the membranes must endure all the fuel cell operations (to prevent crossover of the fuel while still conducting). Their mechanical stress and yielding stress in the recast and impregnation methods compared with the commercial nafion® membrane were obs...

This paper presents the results of mechanical strength of wet and dry zirconia/ Nafion® nano-composite membrane. The tensile tests were conducted to determine elastic modulus and stiffness of dry and wet pristine Nafion® membrane and modified Nafion® membrane. The composite membranes were prepared by recast method of different synthesized zirconium...

A mini-review of defects formation and engineering in energy and sensor materials through intentional doping and microwave irradiation is presented. Intensive research interest has been observed in the development of Transition Metal Oxides (TMOs) energy and sensor materials for industrial applications such as energy generation, energy storage and...

The aim of this paper is to observe the effect of zirconia nanofiller on methanol crossover, mechanical strength and conductivity of modified Nafion® membranes. The impregnation of zirconia nano-rods within the Nafion® matrix obtained the improvements on modulus of elastic in both the dry and wet state, with a decrease in the water contact angle, o...

The paper presents the synthesis and investigation of zirconium oxide (ZrO2) nanoparticles that were synthesized by precipitation method with the effects of the temperatures of reaction on the particles size, morphology, crystallite sizes and stability at high temperature. The reaction temperature effect on the particle size, morphology, crystallit...

Synthesised water-retaining mesoporous zirconia nanoparticles were used to modify Nafion® membrane. This experiment was conducted to enhance the mechanical strength and hydrophilicity of Nafion® membrane for high temperature fuel cell applications. Recast methods were used to prepare a nanocomposite membrane with 10wt% of zirconia nanoparticles. Th...

The aim of this study was to investigate the utilization of milkweed fruit floss residues as a source for the isolation of cellulose. Cellulose was extracted by acidified sodium chlorite and sodium hydroxide treatments. Characterization of the pristine milkweed floss and extracted cellulose was performed by chemical composition analysis, Fourier tr...

Zinc silicate (Zn2SiO4) nanophosphor, doped with manganese (Mn²⁺) and co-doped with europium (Eu³⁺) and dysprosium (Dy³⁺) were synthesized by sol-gel method. In this work the structure, surface and photoluminescence properties of Zn2SiO4: Mn²⁺, Eu³⁺, Dy³⁺ nanophosphor were studied. A broad diffraction peak revealed by X-ray diffraction indicated an...

α-Fe2O3 and α-Fe2O3 doped with different concentration of holmium ions were synthesized by a simple sol-gel method. The XRD data confirmed the hexagonal structure of α-Fe2O3 for un-doped and holmium doped samples. The crystallite size was found to be decreasing with increasing holmium concentration. The amount of holmium was quantified using an EDS...

α-Fe2O3 nanoparticles of crystallite size between 3.9 and 9.5 nm were synthesized by a simple sol-gel method using iron (III) nitrate nonahydrate (Fe(NO3)3·9H2O) as a precursor. Polyvinyl alcohol (PVA) was added as a capping agent to avoid agglomeration of the nanoparticles. A single pure phase was obtained when the sample was annealed at 300 °C an...

Rare–Earth free luminescent materials are fast becoming important as the cost of rare earth ions gradually increases. In this work, a Rare–Earth free BaGa2O4 luminescent compound was prepared by solid state chemical reaction, which was confirmed to have a single phase by X-ray Diffraction. The Backscattered Electron image and Energy Dispersive X-ra...

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...

In the present study, a succession of thulium (Tm)-doped zinc oxide (ZnO) nanostructures samples were prepared by sol-gel method using zinc acetate dihydrate, thulium nitrate pentahydrate and sodium hydroxide species with absolute ethanol as solvent. The X-Ray diffraction (XRD) revealed phase purity (hexagonal Wurtzite structure) and high crystalli...

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...

Green Biosynthesis of Rhodium Nanoparticles Via Aspalathus Linearis Natural Extract This contribution report on the bio-synthesis of Rhodium metallic nanoparticles (Rh NPs) synthesized for the 1st time by a completely green process using Aspalathus linearis natural plant extract as an effective bio-oxidizing/bio-reducing agent as well as a capping...

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...

In this study, we successfully extracted cellulose from borassus fruit fibers by chemical process. The extracted cellulose was dissolved in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl). Using this solution, regenerated cellulose films were prepared with water as the non solvent. The raw fruit fibers and extracted cellulose were cha...

Domestic light providing devices have always been an important component of life and continue to provide us light beyond sunset. These devices continue to be improved frequently to allow ease of use and to enhance their efficiency. The tungsten electric light bulbs are widely used, which are based on incandescence of a continuously heated tungsten...

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...

In this article, we demonstrate the surface effect and optoelectronic properties of holmium (Ho 3+)-doped ZnO in P3HT polymer nanocomposite. We incorporated ZnO:Ho 3+ (0.5 mol% Ho) nanostructures in the pristine P3HT-conjugated polymer and systematically studied the effect of the nanostructures on the optical characteristics. Detailed UV-Vis spectr...

Ruthenium(IV) oxide (RuO2) nanoparticles were synthesized via Aspalathus linearis natural extract as a reducing/oxidizing agent, as well as a capping compound. RuO2 nanoparticles synthesised via a complete green chemistry process would be beneficial for the development of clean, nontoxic and environmentally friendly bio-synthesis procedures. The de...

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 present study reports the synthesis, crystallographic structure and optical properties of manganese (Mn2+) doped zinc silicate (Zn2SiO4) nanoparticle phosphors prepared by sol-gel and combustion methods. For samples prepared by sol-gel method, the X-ray diffraction results showed phase transformation from amorphous to α-phase Zn2SiO4 due to ann...

Undoped and copper doped cadmium sulphide nanoparticles embedded in polyvinyl alcohol matrix (PVA/CdS) were synthesized by adopting chemical route. The effects of doping with Cu on the structural, optical and electrical properties of the as-prepared samples are reported. X-ray diffraction (XRD) results showed a mixed phase of cubic and hexagonal in...