Field Emission Scanning Electron Microscopy Images Research Articles

Sago-shaped embedded nanolayers of WO3/NiO/gC3N4 nanohybrids for natural degradation of environmental pollutants: A photocatalytic sunlight mediated approach

In recent years the applicability of semiconductor nanomaterials is almost in every field of science and technology. In the current study, hybrid nanomaterials containing tungsten trioxide (WO3) and nickel oxide (NiO) supported on graphitic carbon nitride (gC3N4) were prepared by a simple hydrothermal technique. Synthesis was sequential requiring the individual preparation of gC3N4 and WO3 as preliminary. The desired composition of gC3N4, WO3, nickel nitrate, and a base was transferred to an autoclave and maintained at 180°C for 18h. The resulting inorganic/organic hybrid was filtered, washed, dried, and named as inorganic/organic hybrid nanocomposite (HNC). Various compositions of HNC were prepared and characterized by Fourier transform infrared spectrometer (FT-IR), Ultra Violet-Visible Diffuse reflectance spectrometer (UV-Vis-DRS), X-ray diffractometer (XRD), and Field emission scanning electron microscope (FE-SEM). The FE-SEM images showed a sago-shaped embedded particle in gC3N4 layers with a 40-60 nm particle size. The band gap energy was found to be 2.69 eV from UV-Vis-DRS analysis. This proves the promising activity of sago-shaped HNC under sunlight radiation. Various preliminary and kinetic studies were conducted, and HNC possessed excellent photocatalytic activity for the degradation of an organic dye under sunlight. The photocatalytic activity for the degradation of dye by the prepared HNC was found to be two-fold when compared to the activity of pristine gC3N4 under sunlight irradiation.

Gelatin-Coated TiO2/Pd Hybrid: A Potentially Useful Nanomaterial to Enhance Antibacterial and Anticancer Properties.

Hybrid nanomaterials have attracted considerable interest in biomedicine because of their fascinating characteristics and wide range of applications in targeted drug delivery, antibacterial activity, and cancer treatment. This study developed a gelatin-coated Titanium oxide/palladium (TiO2/Pd) hybrid nanomaterial to enhance the antibacterial and anticancer capabilities. Morphological and structural analyses were conducted to characterize the synthesized hybrid nanomaterial. The surface texture of the hybrid nanomaterials was examined by high-resolution transmission electron microscopy (HR-TEM) and field-emission scanning electron microscopy (FE-SEM). The FE-SEM image revealed the bulk of the spherically shaped particles and the aggregated tiny granules. Energy dispersive X-ray spectroscopy (EDS) revealed Ti, Pd, C, and O. X-ray diffraction (XRD) revealed the gelatin-coated TiO2/Pd to be in the anatase form. Fourier transform infrared spectroscopy examined the interactions among the gelatin-coated TiO2/Pd nanoparticles. The gelatin-coated TiO2/Pd nanomaterials exhibited high antibacterial activity against Escherichia coli (22 mm) and Bacillus subtilis (17 mm) compared to individual nanoparticles, confirming the synergistic effect. More importantly, the gelatin-coated TiO2/Pd hybrid nanomaterial exhibited remarkable cytotoxic effects on A549 lung cancer cells which shows a linear increase with the concentration of the nanomaterial. The hybrid nanomaterials displayed higher toxicity to cancer cells than the nanoparticles alone. Furthermore, the cytotoxic activity against human cancer cells was verified by the generation of reactive oxygen species and nuclear damage. Therefore, gelatin-coated TiO2/Pd nanomaterials have potential uses in treating cancer and bacterial infections.

Surface topography and surface morphology of graphene nanocomposite by FESEM, EDX and AFM analysis

The analyzed nanocomposites of this research have been fabricated by the sintering method, where different percentages of boron nitride, zinc oxide, aluminum oxide and titanium oxide have reinforced graphene. The percentages of additives were varied from 0 % to 5 %. An investigation of nanostructural observation, phase identification and structural analysis of graphene nanoparticles has been performed using Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray (EDX) analysis and X-Ray Diffraction (XRD) analysis. The morphology of the synthesized materials was investigated by examining the FESEM pictures at different magnifications. The micrographs depict the hetero-materials' amalgamation, resulting in the formation of compacted particles that collectively exhibit a prominent bulbous morphology. The size and shape of different particles in the nanocomposites are visible from the FESEM images. The assays conducted by EDX have verified the presence of the necessary components, exhibiting a high degree of purity. Further insights about the nanocomposites have been obtained from Atomic Force Microscopy (AFM) analysis. AFM analysis revealed the surface roughness, which increased to 11.9 from 4.4 µm due to the addition of BN. The crystalline structure has been confirmed from the XRD analysis.

An Eco-Friendly Synthesis Approach for Enhanced Photocatalytic and Antibacterial Properties of Copper Oxide Nanoparticles Using Coelastrella terrestris Algal Extract.

In the current scenario, the synthesis of nanoparticles (NPs) using environmentally benign methods has gained significant attention due to their facile processes, cost-effectiveness, and eco-friendly nature. In the present study, copper oxide nanoparticles (CuO NPs) were synthesized usingaqueous extract of Coelastrella terrestrisalgae as a reducing, stabilizing, and capping agent. The synthesized CuO NPs were characterized by X-ray diffraction (XRD), UV-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), and field emission scanning electron microscopy (FE-SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). XRD investigation revealed that the biosynthesized CuO NPs were nanocrystalline with high-phase purity and size in the range of 4.26 nm to 28.51 nm. FTIR spectra confirmed the existence of secondary metabolites on the surface of the synthesized CuO NPs, with characteristic Cu-O vibrations being identified around 600 cm-1, 496 cm-1, and 440 cm-1. The FE-SEM images predicted that the enhancement of the algal extract amount converted the flattened rice-like structures of CuO NPs into flower petal-like structures. Furthermore, the degradation ability of biosynthesized CuO NPs was investigated against Amido black 10B (AB10B) dye. The results displayed that the optimal degradation efficacy of AB10B dye was 94.19%, obtained at 6 pH, 50 ppm concentration of dye, and 0.05 g dosage of CuO NPs in 90 min with a pseudo-first-order rate constant of 0.0296 min-1. The CuO-1 NPs synthesized through algae exhibited notable antibacterial efficacy against S. aureus with a zone of inhibition (ZOI) of 22 mm and against P. aeruginosa with a ZOI of 17 mm. Based on the findings of this study, it can be concluded that utilizing Coelastrella terrestris algae for the synthesis of CuO NPs presents a promising solution for addressing environmental contamination.

Zn complexed on hybrid manganese doped cobalt ferrite nanoparticles covered by silica as a catalyst in the synthesis of 2-amino-4H-pyran and N- arylquinoline derivatives

In the present work, Zn complexed on hybrid manganese doped cobalt ferrite nanoparticles covered by silica were synthesized. These MNPs were characterized using different techniques including Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), Field emission‐scanning electron micro-scope (FE-SEM), Energy‐dispersive X‐ray spectroscopy (EDS), Vibration sample magnetometer (VSM), Inductively coupled plasma atomic emission spectroscopy (ICP), Zeta potential and Thermogravimetric analysis (TGA). FE-SEM Images showed uniform spherical shape with rough surfaces and an aggregation in structure of MNPs. A decrease in Ms is visible in VSM analysis due to the increase in particle diameter as a result of loading the organic coating on the surface of the magnetic nanoparticles. According to TGA analysis, the synthesized MNPs have good stability up to 125 °C. The ICP analysis indicates the presence of 0.13 mmol/g zinc on the surface of loaded MNPs. The effect of these prepared MNPs as a catalyst was studied in the synthesis of 2-amino-4H-pyran and N- arylquinoline derivatives. This method provides excellent yield of products with short reaction time, simple purification and easy separation of the catalyst. Furthermore, the reusability of the catalyst during five periods was not associated with a significant decrease in its activity.

Ferromagnetism behavior of Ni-doped Fe3O4 thin films synthesized by the SILAR technique

In this article, Ni-doped Fe3O4 thin films were synthesized by using the SILAR technique. The films were characterized through X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), Raman, Photoluminescence and UV–Vis analysis. The XRD spectrum confirms the spinal structure of undoped and Ni-doped Fe3O4 thin films. The FESEM images show that Ni-doping has changed the morphology of thin films from a granular to a Spiky structure. The EDAX and XPS spectra show Fe, Ni and O elements are present in 1%Ni-doped Fe3O4 thin film. The vibrating sample magnetometer (VSM) studies showed ferromagnetism in undoped and Ni-doped Fe3O4 thin films. The ferromagnetism behavior of Ni-doped Fe3O4 thin films increases with the increase in Ni ion concentration.

A novel bifunctional electrochemical nanosensor for simultaneous detection of glucose and insulin based on NiO/Co3O4@CuAl LDH-MWCNT nanocomposite-modified carbon paste electrode

The appropriate development of electrocatalytic nanomaterials is a significant step for constructing high-quality non-enzymatic electrochemical sensors. In this work, we presented effective copper aluminum layered double hydroxide (CuAl LDH)-based nanoparticles with two consecutive optimization steps through nickel oxide/cobalt oxide (NiO/Co3O4) merging and subsequent assembly with multi-walled carbon nanotubes (MWCNT). The obtained nanostructures were characterized by using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction pattern (XRD), and field emission scanning electron microscope images (FE-SEM). The synthesized nanomaterials were used as a carbon paste electrode (CPE) material for simultaneous dual-signal evaluation of glucose and insulin. The response of the modified electrode was investigated by some electrochemical approaches, including cyclic voltammetry (CV), electrical impedance (EI), differential pulse voltammetry (DPV), and amperometric titration. The NiO/Co3O4 CuAl LDH@MWCNT electrode displayed multi-functional properties through two well-defined separated peaks toward glucose and insulin detection with a linear range of 0.01–26.5 mM and 0.02–70.0 nM, respectively. The detection limit values were obtained as 2.8 µM for glucose and 17.3 pM for insulin. The sensor showed good tolerance to common interfering agents, excellent sensitivity, and appropriate stability during 30 days of dry storage at room temperature. This sensor was also used for the quantification of glucose and insulin in human serum samples, obtaining the recovery rate of 101.0 %-103.7 % and 98.0 %-106.0 %, respectively, with all the RSD values below 3.0 %. This study represented an efficient simultaneous sensing platform for glucose and insulin detection, which warrants its operational application in clinical samples.

Structural, morphological, and EMI shielding evaluations of Sm-Mn co-doped Sr-based M-type hexaferrite for Ku band applications

High-performance, thin, and lightweight EMI (Electromagnetic interference) materials with outstanding shielding effectiveness were explored over the last years to solve the problems in electronic devices. Magnetic absorbing materials have extensive bandwidth, good impedance matching, and excellent absorption features. In the present study, Sm-Mn Sr-doped M hexaferrites with Sr1-xSmxFe12-yMnyO19 whereas (x= 0.00, 0.025, 0.05, 0.075, y = 0.00, 0.25, 0.5, 0.75) were prepared by the chemical route. XRD, FESEM, HRTEM, FTIR, VSM, and VNA are used to evaluate the properties of the Sm-Mn doped Sr-based M-type hexagonal ferrite. The XRD (X-ray diffraction) results revealed the presence of a hexagonal phase in the prepared samples. Rietveld refinement also confirmed the phase purity for the Sm-Mn doped Sr-based M-type hexagonal ferrites. The FESEM (Field emission scanning electron microscopy) and HRTEM (High-resolution transmission electron microscopy) images revealed the hexagon-type shapes of the particles in the Sm-Mn doped Sr-based M-type hexagonal ferrites. The FTIR (Fourier transform infrared spectroscopy) spectra showed the 446–620 cm-1 lines, confirming the presence of the tetrahedral and octahedral phases of hexagonal ferrites. Dielectric and electromagnetic shielding effectiveness (SE) parameters are evaluated for Sm-Mn doped Sr-based M-type hexagonal ferrite. The electromagnetic parameters, such as complex refractive index, absorption and impedance, are also investigated for the Sm-Mn doped Sr-based hexagonal ferrite powder with x=0.075, y=0.75 having epoxy resin with 20 wt%, 30 wt% and 50 wt% samples, respectively. SE parameters are higher at more extensive filler loading. The green shielding index was found higher for Sm-Mn doped Sr-based hexagonal ferrite powder with x=0.075, y=0.75 having 20 wt% epoxy resin and decreased with filler loading. It is found the epoxy/Sm-Mn doped Sr-based M-type hexagonal ferrites-based composites are excellent absorbers in the Ku band. The investigated absorbers could be the best candidates for next-generation EMI green shielding absorbing devices and applications.

Evolution of fractal characteristics in shales with increasing thermal maturity: Evidence from neutron scattering, N2 physisorption, and FE-SEM imaging

Fractal dimension analysis has become an essential tool to assess the pore structure of various porous geomaterials including shale rock. In this regard, changes of fractal dimension during the thermal maturation of organic rich shale could represent the evolution of its pore structure. To this end, complementary tests were conducted on six organic rich shale samples that are in a wide range of thermal maturity (equivalent Ro values of 0.52–3.53 %). Fractal dimensions were obtained from small-angle neutron scattering (SANS), N2 physisorption, and field emission-scanning electron microscopy (FE-SEM) data. Herein, surface fractal dimensions were calculated from the N2 adsorption isotherms using the Frenkel–Halsey–Hill method, which was found between 2.46 and 2.71. Power-law exponents (E) of the SANS profiles varied from 2.75 to 3.48, indicating that both surface fractals and mass fractals would characterize the shale samples. As thermal maturity progressed, the fractal dimension shifted from surface to mass fractal while further analyses suggested this was caused by changes in the number density of pores (NDP) of various pore-size ranges. Ultimately, the pore size of the samples during such transition decreased with the increase of Ro.

Unveiling the petrographical, palynological, palynofacies and geochemical archives of coal and shaly coal deposits in the Mandakini–B block of Talcher Basin: An insight into the paleoecology, depositional environment, kerogen type and source rock potential

Coal and shaly coal beds in the Talcher-Mahanadi Basin, eastern India, belongs to Barakar Formation (Artinskian). A comprehensive analysis was undertaken, including organic petrography, palynology, palynofacies, proximate analysis, Rock-Eval pyrolysis and Field Emission Scanning Electron Microscopy (FE-SEM). The samples consist of the vitrinite group of macerals (avg. 38.2 vol.%), followed by inertinite and liptinite, suggesting peat-forming higher plant vegetation was deposited under prevailing anaerobic conditions. However, the significant presence of inertinite macerals (avg. 29.2 vol.%), including semifusinite and fusinite, along with opaque phytoclasts (avg. 17.3 %), implies occasional shift to oxic conditions. High occurrence of tissue-derived phytoclasts (avg. 64.3 %) indicates that higher plants were the primary contributors to peat formation. Detrovitrinite sub-groups and non-biostructure phytoclasts suggests contributions from herbaceous flora and/or potential tissue degradation due to microbial activity. The palynomorph distribution reveals the dominance of Glossoptriadales, followed by Coniferales and trilete spore groups, comprising 25 genera and 40 species. Non-striate bisaccate pollen, primarily Scheuringipollenites (15–34 %) and sub-dominant striate bisaccate pollen Faunipollenites (11–18 %) prevail in the palynoassemblage. Petrographic indices suggest that the deposition of peat-forming telmatic vegetation has largely occurred in wet forest swamp conditions within the mesotrophic hydrological setting. Palynofacies data, plotted on Tyson’s APP (Amorphous organic matter-Phytoclast-Palynomorph) ternary diagram, suggests suboxic to dysoxic deposition conditions. Low phytoclast preservation index (PPI) indicate proximal deposition of the organic matter. Vitrinite reflectance (VRo%) ranged between 0.42 and 0.68 %, suggesting that the coalification reached up to ‘Medium rank D’ or Bituminous D stage. The substantial total organic contents (TOC: 34.02–61.84 wt.%), hydrogen index (HI) (avg. 154 mg HC/gTOC) and dominance of vitrinite maceral/non-opaque phytoclasts indicate Kerogen Type III and have significant potential for gaseous hydrocarbon generation. FE-SEM images reveal well-developed intergranular and organic pores within the matrix system, serving as both a source and storage in coal beds.

Zeolite-Based Poly(vinylidene fluoride) Ultrafiltration Membrane: Characterization and Molecular Weight Cut-Off Estimation with Support Vector Regression Modelling.

Zeolite serves as a promising additive for enhancing the hydrophilicity of polymeric membranes, yet its utilization for bolstering the mechanical strength of the membrane remains limited. In this study, poly(vinylidene fluoride) (PVDF) membranes were modified by incorporating various concentrations of zeolite (0.5-2 wt%) to improve not only their mechanical properties, but also other features for water filtration. Membranes with and without zeolite incorporation were fabricated via a dry-wet phase inversion technique, followed by the application of a series of characterization techniques in order to study their morphological structure, mechanical strength, and hydrophilicity. The membrane filtration performance for each membrane was evaluated based on pure water flux and Bovine Serum Albumin (BSA) rejection. Field-Emission Scanning Electron Microscopy (FESEM) images revealed a dense, microvoid-free structure across all of the PVDF membranes, contributing to a high pristine PVDF membrane tensile strength of 14 MPa. The addition of 0.5 wt% zeolite significantly improved the tensile strength up to 19.4 MPa. Additionally, the incorporation of 1 wt% zeolite into PVDF membrane yielded improvements in membrane hydrophilicity (contact angle of 67.84°), pure water flux (63.49% increase), and high BSA rejection (95.76%) compared to pristine PVDF membranes. To further improve the characterization of the zeolite-modified PVDF membranes, the Support Vector Regression (SVR) model was adopted to estimate the molecular weight cut off (MWCO) of the membranes. A coefficient of determination (R2) value of 0.855 was obtained, suggesting that the SVR model predicted the MWCO accurately. The findings of this study showed that the utilization of zeolite is promising in enhancing both the mechanical properties and separation performance of PVDF membranes for application in ultrafiltration processes.

Targeted Drug Delivery through the Synthesis of Magnetite Nanoparticle by Co-Precipitation Method and Creating a Silica Coating on it

Billions of dollars are spent annually in the world to treat and investigate problems caused by drug side effects. According to the estimation of health researchers, a huge part of people who take medicine suffer from complications caused by it. In this way, the necessity of using a targeted system in order to deliver medicine to the targeted place without damaging healthy tissues is felt more than before. In recent years, targeted drug delivery systems based on nanoparticles have received much attention. In the same direction, in this research, co-precipitation method was used to prepare magnetic nanoparticles using iron(|) and iron(||) oxides, and further, according to the synthesis steps of magnetite nanoparticles (MNPs) and the mechanism of formation and identification of magnetite nanoparticles ( Fe3O4) by examining the infrared pattern (FT-IR) obtained from Fe3O4 nanoparticles, the results of the magnetometric test (VSM) of Fe3O4 nanoparticles, X-ray diffraction pattern (XRD) of Fe3O4 nanoparticles, Field Emission Scanning Electron Microscope (FE-SEM) images obtained from Fe3O4 nanoparticles was discussed. After this stage, silica- coated iron nanoparticles (Fe3O4@SiO2) were prepared, and the infrared (FT-IR) pattern of Fe3O4@SiO2) was also investigated. It is worth mentioning that the mechanism of formation and identification of magnetic silica-coated iron nanoparticles (Fe3O4@SiO2) has been described in detail. Therefore, the obtained results indicate that the drug can be guided in a controlled and targeted manner by the magnetic field, and the results of the FE-SEM images show that the obtained product has a spherical morphology and the particle size distribution was less than 100 nm. Therefore, spherical shape and the symmetry of these particles can be helpful for their movement in the liquid mediu.

Influence of synthesis route on structural properties of SnFe2O4 spinel phase via methods of co-precipitation, sol–gel and solvothermal: morphology, phase analysis, crystallite size and lattice strain

In this study, regarding to the wide applications of spinel ferrites in various fields such as Li ion-batteries, photocatalysts, and optoelectronics, the structural and morphological properties of tin ferrite oxide (SnFe2O4) nanoparticles are investigated using X-ray diffraction (XRD) analysis and field emission scanning electron microscopy (FESEM). The sol–gel, solvothermal, and co-precipitation methods were used to synthesize the SnFe2O4 nanoparticles, and the effect of annealing temperatures at T = 350 °C, 450 °C, and 550 °C was investigated. The XRD results confirmed the formation of tin ferrite spinel phase at an annealing temperature of 350 °C with a preferred peak (311). Crystallite size (D) and strain (ε) of SnFe2O4 nanoparticles was determined in region 20–45 nm and 2–4 × 10–4, respectively, using the Scherer, Williamson–Hall, and Rietveld computational methods. The results showed that the crystallite size in the samples increased with increasing annealing temperature. This increase is attributed to the reduction of defects, imperfections and lattice strain, which leading to an increase in the lattice constants and unit cell volume in the nanocrystalline structure. The Rietveld method determine smaller crystal sizes compared to the Williamson–Hall and Scherer methods because it can correct for peak broadening by taking into account all instrumental factors. The FESEM images of the synthesized nanostructures of SnFe2O4 showed cubic and polyhedral grains with cluster growth and an average grain size of 50–80 nm. According to the crystal structure of tin ferrite spinel, the cubic morphology confirmed the formation of this structure. The average crystallite size and grains in the synthesized samples was determined using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) analysis, respectively. The formation conditions of the SnFe2O4 spinel phase and other phases in the synthesis process at different temperatures and dependence of structural parameters was studied by various structural models for the samples.

Graphene aerogel based positive electrode for lithium ion batteries

In this study, a composite of LiNi0.8Mn0.1Co0.1O2 nanoparticles (nNMC-811) supported by three-dimensional (3D) graphene aerogel (GA) was prepared to increase the practical energy density and performance capability of high nickel cathodes. The porous LiNi0.8Mn0.1Co0.1O2 nanoparticle/graphene aerogel (nNMC-811/GA) composite is composed of nNMC-811 and graphene that act as a bridge for electron transfer and acceleration of lithium ion diffusion. nNMC-811 and nNMC-811/GA cathodes characterization data with techniques including X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectra (FT-IR) and X-ray photoelectron spectroscopy (XPS) are discussed. Both Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM) made clear observations of the uniform distribution of the cathode active powders over the 3D graphene aerogel structure. The electrochemical performance of the nNMC-811 and nNMC-811/GA cathodes was evaluated by the galvanostatic charge-discharge measurement between 2.5 V and 4.5 V at room temperature using a computer-controlled battery tester. In addition, variable speed capacity ratios (C-rate), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) analyzes were also performed. nNMC-811/GA hybrid composite structure delivers a specific capacity of 183.15 mAhg−1 at C/2 after the 500th cycle. It is understood from the FE-SEM images taken after the cycle that there is no deterioration in the structure. According to results, it was observed that the 3D porous structure of the nNMC-811/GA composite facilitated the mobility of Li+ ions, and the excellent electrochemical performances of the cathodes were improved due to the increasing defects as well as the electrical conductivity of GA.

Optical and electrochemical properties of manganese oxide (Mn3O4) nanoparticles: Investigating the influence of calcination temperature on supercapacitor performance

In this study, we investigate the influence of calcination temperature on the structural, optical, and electrochemical properties of Mn3O4 nanoparticles synthesized through a chemical co-precipitation route. Field-Emission Scanning Electron Microscopy (FESEM) images depict the formation of highly agglomerated, spherical-shaped particles. At calcination temperatures of 700 °C and 900 °C, the observation reveals the emergence of flat pellets and rod-like structures. The X-ray Diffraction (XRD) patterns confirm the presence of the Mn3O4 phase in M0 and M1 samples. However, the sample calcined at 500 °C (M3) showed a mixed phase of Mn3O4 and Mn2O3. Upon further calcination at 700 and 900 °C, this mixed phase undergoes complete transformation into the Mn2O3 phase. The change in absorption onset and photoluminescence intensity of samples is found with an increase in calcination temperature due to the crystal growth and phase modification. Furthermore, the synthesized samples are employed as electrode materials for supercapacitor applications. The sample calcined at 300 °C (M1) in three-electrode system demonstrated the specific capacitance (Csp) of 273.3 F/g at 0.5 A/g in an alkaline medium. The asymmetric cell assembled by using M1 and Hibiscus cannabinus stem-derived carbon material (HBC-900) delivered higher Csp of 205.7 F/g at 0.5 A/g. In addition, asymmetric supercapacitor device exhibited a high energy and power density of 43.1 Wh/kg and 476.2 W/kg with 82.07 % of initial Csp retention over 10,000 cycles at 10 A/g, which makes the sample M1 as the potential electrode material for supercapacitor application.

Influence of NaOH Concentration on Structural, Morphological, Optical, and Electrical Characterization of Perovskite Sodium Bismuth Titanate Prepared by Hydrothermal Method

The hydrothermal method successfully prepares a lead-free sodium bismuth titanate (NBT) perovskite film. The prepared films were studied structurally, and morphologically using X-ray diffraction, and field-emission scanning electron microscopy (FESEM), respectively. Varying the concentration of NaOH showed a noticeable effect on the properties studied. Good crystallization of NBT perovskite films without impurities was obtained at 18 and 20 M concentrations, where the crystalline size was 14 nm according to the Scherer equation. Also, when varying the concentration of NaOH, a similar film thickness was obtained through a cross-section of the FESEM images. It was observed that there was a difference in the intensity of the peaks of the photoluminescence spectra of the prepared films with a change in the concentration of NaOH, which confirms a change in the concentration of oxygen vacancies. The activation energy of the prepared films was deduced from the Arrhenius plot, as it showed small values in the films prepared with a low concentration of NaOH. The results showed that the maximum value of mobility of NBT films was at 20 M of NaOH concentration through the Hall Effect.

Structural and Electrical Properties of Li Substituted Mg Nano Ferrites: Prepared by Citrate-gel Auto Combustion Method

LixMg1−xFe2O4 where x=0.0to0.5with0.1 nano ferrites were synthesized by citrate gel auto combustion. Using a field-emission scanning electron microscope (FE-SEM) and the X-ray diffraction technique, their structural and topographical studies were examined. The prepared nano ferrites’ single-phase cubic spinel along the Fd3m space group is confirmed by the structural investigation. The synthesized samples were found to have a crystalline size of 20–26 nm, as determined by the Debye–Scherrer formula. Lattice parameter variation observed for the samples indicates dopant atoms into a crystal lattice can also lead to changes in the lattice constant. FE-SEM images revealed the clear grain and grain boundaries with agglomerated structure and it varied between 33.6 nm-24.4 nm. Two bands observed in Fourier transform infrared spectroscopy illustrates the M-O band in tetrahedral and octahedral sites. Dielectric parameters of the sample observed by LCR meter. Single semicircle behavior observed in impedance spectra. Dielectric constant and dielectric loss decreased as increasing frequency explained by Koop’s theory of mechanism. AC conductivity increasing trend observed with frequency, mobility of charge carrier active at high frequency domain.

Effect of oxidation temperature on physical properties of polycrystalline β-Ga2O3 grown by thermal oxidation of GaN in O2 ambient from 900 to 1400 °C

This study aimed to investigate the effect of oxidation temperature on the physical properties of β-Ga2O3 grown by thermal oxidation of GaN in the O2 ambient at high oxidation temperatures from 900 to 1400 °C. Notably, the analysis of the oxidation temperatures ranging from 1100 to 1400 °C remains unexplored in the other studies. The effects of the oxidation temperature on the physical properties were investigated via X-ray diffraction, X-ray photoelectron spectroscopy, and field-emission scanning electron microscopy (FESEM). At all oxidation temperatures, XPS results revealed oxygen deficiency. The top FESEM images indicated disordered nanocolumn structures on the surface of the oxide layer, which increased in abundance with oxidation temperatures exceeding 1100 °C. Energy-filtered high-resolution transmission electron microscopy images and the selected area electron diffraction patterns revealed that the top nanocolumns and the oxidized layer comprised polycrystalline β-Ga2O3. Additionally, the cross-sectional lamellae prepared through focused ion beam milling revealed an increase in the thickness of the β-Ga2O3 layer with oxidation temperature. To account for the variations in the oxide layer thickness, the oxidation temperatures were classified into two ranges of 900–1100 °C and 1100–1400 °C for calculating the activation energy. Moreover, this study assumed that the activation energy required for the oxidation process remained constant within each temperature interval. According to Arrhenius's model, the activation energy from 900 to 1100 °C was calculated to be 286.15 kJ/mol (2.97 eV). Furthermore, the activation energy from 1100 to 1400 °C was determined to be 111.33 kJ/mol (1.15 eV).

Comparative Study of Rare Earth Nd and Sm Doping on the Structural, Morphological, Optical, Magnetic, and Electromagnetic Traits of Mg-Zn-Cu Spinel Nanoferrites

In the current study, the magnetic nanoparticles of neodymium and samarium substituted Mg-Zn-Cu, with a chemical composition of Mg0.5Zn0.5Cu0.05RxFe1.95-xO4 (x = 0.05; R = Nd, Sm) were produced via the sol-gel auto-combustion route. XRD indicates the evolution of a cubic symmetry having Fd3m space group and no impurities at the room temperature. The FESEM images show the irregularly shaped and agglomerated grains in all samples. FTIR examination reveals the stretching vibrations among the metal cations and anions at interstitial vacancies. The M-H graphs demonstrates that the prepared nanoferrites have low rentivity (0.18–0.84 emu g−1) and coercivity (11.25–34.03 Oe) indicating the formation of superparamagnetic nature. From the electromagnetic traits, the observed sample’s real magnetic permeability (μ″) and permittivity (ε′) along with dielectric loss and magnetic loss reduced with increasing applied field frequency, indicating the typical behaviour of spinel nanoferrites. This may be explained by Maxwell-Wagner interfacial polarisation and the electron hopping among the ferrous and ferric ions. The variations in coercivity, anisotropy constant, and electromagnetic traits provide strong evidence that all of the samples are thermally stable and have the potential to be used in solenoids and transformers, and also, in the more resistive devices that operate at the high frequency.

The influence of the physicochemical processes on the electrical response of Al/p-Si structure with etched surface

In this paper, the electrochemical etching process is used for surface modification of the p-Si wafer, named as porous silicon (PS), in the metal–semiconductor (MS) type Schottky diode (SD) with a structure of Al/p-Si. Five regions of PS wafer with different etching rates are selected for comparison of them which are called P2, P3, P4, and P5 (P1 is the reference area without porosity). The morphological, structural, and electrical properties of the PS used in the MS-type SD are investigated using field-emission scanning electron microscope (FE-SEM) images, energy dispersive X-ray (EDX) analysis, and current–voltage (I–V) characteristics, respectively. The FE-SEM images show a meaningful effect on the porosity. The EDX spectrum demonstrates the importance of the chemical effects in addition to the physical changes in the porosity process of the p-Si wafer. The reverse-saturation current (I0), ideality factor (n), barrier height at zero-bias (ΦB0), and series/shunt electrical resistances are also computed and compared. Some of these parameters (n, Rs, BH) are determined using different methods, namely Thermionic emission (TE), Cheung functions, and modified Norde, and they exhibit strong agreement with each other. The energy-dependent profiles of surface states (Nss) are estimated from the I–V data by considering the voltage dependence of ΦB (V) and n(V). All the experimental findings indicate that the etching process of the p-Si wafer significantly influences the electrical performance of the Al/p-Si Schottky diode by increasing the extent of etching.