Halder-Wagner Methods Research Articles

The effect of thermal annealing of GO/PVA on their physical, structural, and morphological properties

ABSTRACT In this research the synthesis of graphene oxide (GO) through the Hummers method, to obtain various percentage nanocomposite materials incorporating GO into polyvinyl alcohol (PVA) (2%GO/PVA, 3%GO/PVA, and 20%GO/PVA), and the detailed investigation of these composites’ morphological, structural, and optical characteristics using X-ray diffraction (XRD), Fourier-transform infrared (FTIR), Raman spectroscopy, and Scanning electron microscopy (SEM). The main goal of the presented work is to investigate how the physical properties change in the wide-range concentrations of the GO/PVA composite materials, as well as at different thermal annealing temperatures. From the XRD results, the space between the sheets is decreased by increasing the thermal annealing temperature. By the Halder-Wagner method, crystallite size and microstrain of the various percentages of GO/PVA were determined. The high microstrain and crystallite size belong to thermal annealed at 70°C of 3% GO/PVA (D = 8.50 nm/ε = 11%) and thermal annealed at 40°C of 20% GO/PVA (D = 13.70 nm/ε = 16 %). At room temperature and the highest annealing temperature, the microstrain value is minimal or equal to 0, because, its crystal structure is stable at low temperatures and it occurs as a result of relaxation due to rearrangement of the polymer chain at high temperatures. From Raman measurements, the ID/IG ratio for 2% and 3% GO/PVA composite materials increased with increasing temperature compared to the pristine GO. This indicates that the defect in the structure increases due to temperature.

Comparative microstructural analysis of V2O5 nanoparticles via x-ray diffraction (XRD) technique

Vanadium pentoxide (V2O5) nanoparticles exhibit diverse properties and have been studied for a wide range of applications, including energy storage, catalysis, environmental remediation, and material enhancement. In this work, we have reported the synthesis of vanadium pentaoxide (V2O5) nanoparticles using hydrothermal method. Ammonium metavanadate (NH4VO3) was used as a source of vanadium. These syntheses were carried out at four different concentrations of vanadium source. The hydrothermal reaction was conducted at a temperature of 180 °C for a duration of 24 hours, followed by an additional 24 hours period of natural cooling. Four samples were annealed in air using a muffle furnace at 500 °C for five hours. The x-ray diffraction technique was used to study the structural aspects. A comparative analysis of the microstructure was conducted utilizing the Scherrer method, the Williamson–Hall method and its various models, size-strain analysis, and the Halder–Wagner method. The crystallite size and microstrain were determined using these distinct methods, revealing a systematic correlation between the crystallite size and microstrain obtained through the different techniques.

Photocatalytic and electrochemical investigation of Mn and Sn co-doped ZnO nanoparticles: Effect of doping concentration

The chemical precipitation method is employed to prepare the Mn and Sn co-doped ZnO nanoparticles with various doping concentrations. Debye Scherrer’s formula, Williamson-Hall equation and Halder-Wagner methods are used to calculate the crystallite size of the prepared nanoparticles. The addition of dopants enhances the periodicity of the atoms. The bond lengths, second nearest neighbor distances and bond angles are examined. The purity of the samples is confirmed using energy dispersive X-ray analysis technique. The process of doping reduces the maximum optical absorption. The dopants reduce the band gap of the prepared nanoparticles and the band gap ranges from 3.07 eV to 3.03 eV. The charge carrier concentrations are calculated from the optical band gap. The Hall coefficient of the prepared nanoparticles increases due to the addition of the dopants. The refractive index of the material is also examined. The quenching is observed in the photoluminescence spectrum due to the dopants. The dielectric properties and electric modulus depend on doping concentrations of Mn and Sn. The degradation of the Congo red and methylene blue dyes with prepared nanoparticles as catalysis is reported. The specific charge of the Mn and Sn co-doped ZnO-based electrode is analyzed using cyclic voltammetric study and galvanostatic charge–discharge technique.

Evaluation of anti-microbial activity of biotite and biotite composite based on crystallographic parameters: Estimation of crystallite size employing X-ray diffraction data

This study dealt with naturally occurring biotite from the river sediment to synthesize biotite based composite to evaluate antimicrobial activities against gram positive bacteria, negative bacteria and fungi. Biotite mineral, and synthesized carbon aerogel –biotite (CBt) composite and carbon aerogel-biotite –ZnO (CBtZ) composites were considered for the antimicrobial study. The samples were characterized by X-ray diffraction technique and different crystallographic parameters were computed applying X-ray diffraction data. Also, FESEM was performed to understand the surface morphology of the samples. Crystal size of the biotite, CBt and CBtZ were computed 103.215, 57.567, and 36.496 nm respectively. Tabulated microstrain are 0.175, 0.499 and 0.935 for the biotite, CBt and CBtZ respectively. Various models and equations were used to justify crystallite size, including the Williamson-Hall plot, linear straight line model, Scherrer equation, Monshi-Scherrer model, Size-strain plot (SSP) model, Halder-Wagner method and Sahadat-Scherrer model. For the both composite samples, following models confirmrd the presence of nanocrystal with a range of 50.789–97.777 nm (CBt) and 36.496–105.843 nm(CBtZ). However, for the biotite, all mentioned models were proved invalid except scherrer equation, SSP model and Monshi-Scherrer model. Linear straight line model was found invalid to calculate crystallite size of the three samples. Moreover, different crystal parameters like dislocation density, volume of the unit cell, lattice parameters were computed. Zone of inhabitation estimation method was employed to estimate antimicrobial activity against Listeria monocytogenes, Staphylococcus aureus, Salmonella abony, Escherichia coli and Candida albicans. Required minimum inhibitory concentration (MIC) together with minimum bactericidal concentration (MBC) also estimated in this study. Crystal size effect on the antimicrobial activities of the samples were evaluated in this study.

Evaluation of structural parameters of monoclinic nanocrystalline CuO and study of sunlight-driven photocatalytic dye degradation, antimicrobial and antioxidant potential

Highly pure, crystalline and spherical-shaped Copper oxide nanoparticles (NPs) have been synthesized via facile chemical coprecipitation. Various models including the Scherrer, Monshi-Scherrer, Williamson-Hall, Size-Strain Plot and Halder-Wagner method have been applied to study the crystal structure characteristics. The lattice parameters associated with the monoclinic crystal lattice of CuO NPs were estimated to be a = 4.69 Å, b = 3.41 Å, c = 5.14 Å and β = 99.87(degree), unit cell volume V = 81.35Å3 and cell density dx = 6.49 g/cm3. The photocatalytic dye degradation proficiency at 20 mg/l CuO concentration and 120 min sunlight exposure results the order of percentage dye degradation Malachite Green (88.4%) > Crystal Violet (70.8%) > Eosin Yellow (70.2%) > Methylene Blue (54.08%) dyes. The antimicrobial activity assessment was done against the broad-spectrum pathogenic microbes unveiled the exceptional microbial controlling capability of CuO NPs. Furthermore, the antioxidant activity test demonstrated the potential free radical scavenging activity of CuO NPs with an IC50 value of 47.733 µg/ml. Highlights Synthesis of pure and spherical shaped nanocrystalline CuO was done by using low cost and facile chemical coprecipitation method. XRD, FTIR, FESEM, EDX, UV-Vis, and Raman spectroscopic techniques were used for characterization purpose. The structural and crystallographic parameters of monoclinic crystal structure of CuO NPs were evaluated successfully. The photocatalytic performance of CuO NPs follow the percentage dye degradation order as MG (88.4%) > CV (70.8%) > EY (70.20%) > MB (54.08%) after 120 minutes of sunlight exposure. CuO NPs exhibit promising antifungal activity against COVID-19 associated Pulmonary Aspergillosis (CAPA) causing pathogenic fung. CuO NPs show potential DPPH free radical scavenging activity with an IC50 value of 47.733 µg/ml.

X-ray diffraction analysis of orthorhombic SnSe nanoparticles by Williamson–Hall, Halder–Wagner and Size–Strain plot methods

SnSe nanoparticles were synthesized using the sonochemical exfoliation technique, employing SnSe single crystals. Various analysis, including Energy Dispersive Analysis of X-rays-Elemental mapping, X-ray Diffraction (XRD), High-Resolution Transmission Electron Microscopy, Ultra-Violet Diffused Reflectance Spectroscopy-Photoluminescence measurements, Raman spectroscopy, and X-ray Photoelectron Spectroscopy, were conducted to determine the chemical composition, crystalline phase, morphological characteristics, optical properties, vibrational modes, and oxidation states of the synthesized nanoparticles. The XRD peak broadening analysis, specifically employing Williamson–Hall (W-H), Size–Strain Plot (SSP), and Halder–Wagner Method (H-W), was employed to examine particle size and intrinsic strain. Additionally, three models within the W-H method, namely the uniform deformation model (UDM), uniform stress deformation model (USDM), and uniform deformation energy density model (UDEDM), were used to investigate physical and microstructural parameters such as strain, stress, and energy density. A comprehensive comparison of the average particle size results obtained from Williamson–Hall, Size–Strain, and Halder–Wagner Methods, along with results from HR-TEM and Particle Size Analysis, was carried out. The comprehensive comparison of results from different techniques adds credibility to the reported findings.

A comparative study in estimating of crystallite sizes of synthesized and natural hydroxyapatites using Scherrer Method, Williamson-Hall model, Size-Strain Plot and Halder-Wagner Method

In this study, an approach was made to create hydroxyapatite (HAp) crystals on nanoscale ranges from CaCO3 and H3PO4 utilizing a wet chemical process. Both fish and cow bones were used effectively for making bone powder as the natural sources of HAp. X-ray diffraction approach proved that powdered bone and HAp were in the crystalline phase. The determination of crystallite size in synthesized HAp crystals and bone powders was investigated using a range of techniques, including Linear Straight-Line Method (LSLM), Williamson-Hall Method (WHM), Size-Strain Plot (SSP), Halder-Wagner Method (HWM), and Sahadat-Scherrer Method (SSM). We also employed different Williamson-Hall models to quantify the stress and strain of the powdered materials for all diffraction peaks, including the Uniform Deformation Model (UDM), Uniform Stress Deformation Model (USDM), and Uniform Deformation Energy Density Model (UDEDM). Williamson-Hall is regarded as the best approach out of all of them since it was used to find the energy density, lattice stress, lattice strain, and crystallite size of the formed crystal. All the results from each model were compared to check the variation of analyzed data. The obtained results confirmed that there was an interrelation between the particle sizes of the Size Strain Plot and the Williamson-Hall method.

Gd2O3/CdS Nanocomposites were Synthesized for Photocatalytic Elimination of Methyl Blue (MB) Dye Under Visible Light Irradiation

Water contamination with hazardous dyes is a serious environmental issue that concerns humanity. A green technology to resolve this issue is the use of highly efficient photocatalysts under visible light to degrade these organic molecules. Adding composite and modifying shape and size on semiconductor materials are attempts to improve the efficacy of these compositions. The optical, microstructural and photocatalytic features of the compositions were investigated by several characterization procedures such as XRD, XPS, SEM, and TEM. Here, modifies Scherrer equation, Williamson–Hall (W–H), and Halder–Wagner method (H–W) have been used to investigate the crystal size and the micro-strain from the XRD peak broadening analysis. The average crystal size according to Modified Scherrer’s formula was 6.04–10.46 nm for pristine CdS and CdS/Gd2O3@GO, respectively. While the micro-strain (ɛ) corresponds to 3.88, 4.63, 4.03, and 4.15 for CdS, Gd2O3, CdS/Gd2O3, and CdS/Gd2O3@GO. It was also shown that the modest difference in average crystal size acquired by the Modified Scherrer and Halder–Wagner (HW) forms was related to differences in average particle size classification. As a result, the Halder–Wagner method was accurate in estimating crystallite size for the compositions. The average roughness is slightly changed from 4.4 to 4.24 nm for CdS/Gd2O3 and CdS/Gd2O3@GO, respectively. A kinetics investigation further revealed that the photocatalytic degradation of MB dyes was accompanied by a Langmuir isotherm and a pseudo-second-order reaction rate. The highest adsorption capacity (qe) determined for (type 1) CdS, Gd2O3, CdS/Gd2O3, and CdS/Gd2O3@GO adsorption was 5, 0.067, 0.027, and 0.012 mgg−1, respectively. The R2 values originated from the pseudo-second-order (type 2) for CdS, Gd2O3, CdS/Gd2O3, and CdS/ Gd2O3@GO were 0.904, 0,928, 0.825, and 0.977. As a result, the initial sorption rate (h) is altered between types 1 and 2. In type 2, the pseudo-second-order rate constant (k2) ranges from 0.005 for CdS to 0.011 for CdS/Gd2O3@GO. The Langmuir Hinshelwood and pseudo-second-order kinetic models describe the photodegradation process. The results demonstrate that the developed compositions can be used as a long-term substance for dye removal.

Synthesis of nano-crystallite hydroxyapatites in different media and a comparative study for estimation of crystallite size using Scherrer method, Halder-Wagner method size-strain plot, and Williamson-Hall model

Hydroxyapatite (HAp) [Ca10(PO4)6(OH)2] is remarkably similar to the hard tissue of the human body and the uses of this material in various fields in addition to the medical sector are increasing day by day. In this research, mustered oil, soybean oil, as well as coconut oil were employed as liquid media for synthesizing nanocrystalline HAp using a wet chemical precipitation approach. The X-ray diffraction (XRD) study verified the crystalline phase of the HAp in all the indicated media and discovered similarities with the standard database. Several prominent models such as the Scherrer's Method (SM), Halder-Wagner Method (HWM), linear straight-line method (LSLM), Williamson-Hall Method (W-M), Monshi Scherrer Method (MSM), Size-Strain Plot Method (SSPM), Sahadat-Scherrer Method (S–S) were applied for the determination of crystallite size. The stress, strain, and energy density were also computed from the above models. All the models, without the Linear straight-line technique of Scherrer's equation, resulted in an appropriate value of crystallite size for synthesized products. The calculated crystallite sizes were 6.5 nm for HAp in master oil using Halder-Wagner Method, and 143 nm for HAp in coconut oil using the Scherrer equation which were the lowest and the largest, respectively.

Synthesis of pure and Cd-doped hydroxyapatite for the photo-catalytic degradation of Amoxicillin and Ciprofloxacin: Crystallographic characterization using XRD

Nanosized hydroxyapatite (HAp) is considered an elementary material for artificial bone tissue engineering and the applications are expanding and one of them is the photocatalytic degradation of environmentally hazardous pollutants. In this research, HAp nanoparticles, in pure form and doped with cadmium (Cd), were synthesized using a conventional wet-chemical precipitation method. Additionally, the synthesized samples such as pure and Cd-doped HAp were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–Vis spectroscopy. Moreover, the XRD analysis allowed for a detailed estimation of the crystallite size, assisting in their tailoring of increased photocatalytic activity. The crystallite sizes of the nano-crystallite Hap were evaluated using the Scherrer Method (SM), Williamson-Hall Method (WHM), Size-Strain Plot (SSP), Halder-Wagner Method (HWM), and Sahadat-Scherrer Method (SSM). The models confirmed the formation of nano crystallite hydroxyapatite in pure and doped form. Cadmium doping in HAp showed great photocatalytic activity for example at 150 min, 31 % amoxicillin and 52 % ciprofloxacin were degraded upon 1.5 wt % Cd doping in HAp crystal. The research demonstrated that doping Cd in HAp crystal improved photocatalytic activity towards antibiotic solution (ciprofloxacin and amoxicillin) under all test circumstances.

The influence of Nd3+ doping on the structural, optical, magnetic, and dielectric characteristics of nanoscale hexagonal wurtzite type ZnO

Nd3+ doped ZnO nanoparticles (NPs) Zn1−xNdxO (x = 0, 0.01, 0.03, and 0.05) were successfully synthesized via simple co-precipitation method. To extract precise crystallite size and lattice strain from the X-Ray Diffraction (XRD) pattern, Halder-Wagner method was employed. High Resolution Transmission Electron Microscopy (HRTEM) analysis clearly substantiates the NPs formation.The band gap variation in the doped samples in comparison with the pristine sample is extracted from UV–Vis diffuse reflection spectroscopy. The decrease in Photo-luminance (PL) intensity is observed to be significant for enhanced photocatalytic applications. At room temperature (RT), all Nd3+doped ZnO samples exhibit a distinct hysteretic loop. The initial magnetization graph and M-T curve fitted by the modified Brillouin function and combination of spin wave and Curie-Weiss law respectively. The well-fittings indicate the co-existence of paramagnetic (PM) and ferromagnetic (FM) phases in the doped sample, and the quantitative contribution to each phase is also extracted. Significantly high dielectric constant and low ac conductivity at a low frequency region support the presence of large dipolar effect-induced frequency-dependent short-range conductivity in these pristine and Nd3+ doped ZnO samples.

Synthesis of different types of nano-hydroxyapatites for efficient photocatalytic degradation of textile dye (Congo red): a crystallographic characterization.

The textile industry, a vital economic force in developing nations, faces significant challenges including the release of undesired dye effluents, posing potential health and environmental risks which need to be minimized with the aid of sustainable materials. This study focuses on the photocatalytic potential of hydroxyapatite together with different dopants like titanium-di-oxide (TiO2) and zinc oxide (ZnO). Here, we synthesized hydroxyapatite (HAp) using different calcium sources (calcium hydroxide, calcium carbonate) and phosphorous sources (phosphoric acid, diammonium hydrogen phosphate) precursors through a wet chemical precipitation technique. Pure and doped HAp were characterized via different technologies, which consist of X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), as well as UV-vis spectroscopy. The effectiveness of the synthesized photocatalyst was evaluated by its interactivity with synthetic azo dyes (Congo red). The photodegradation of Ca(OH)2_HAp, CaCO3_HAp, ZnO-doped HAp as well as TiO2-doped HAp, were obtained as 89%, 91%, 86%, and 91%, respectively. Furthermore, at neutral pH, TiO2-doped HAp shows the highest degradation (86%), whereas ZnO-doped HAp possesses the lowest degradation (73%). Additionally, various XRD models (Monshi-Scherrer's, Williamson-Hall, and Halder-Wagner methods) were employed to study crystallite dimension.

Different solvents and organic modifiers for the control of crystallographic parameters in nano-crystallite hydroxyapatite for amplification of photocatalytic activity.

In this research, HAp nanocrystals were synthesized using conventional wet chemical precipitation methods using various organic modifiers, including urea, palmitic acid, and naphthalene. Ethanol and isopropyl alcohol (IPA) were used as solvents in this process. Different characterization techniques, namely X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-vis absorption spectroscopy, were employed to ascertain the formation of HAp nanocrystals. Numerous structural parameters, including lattice parameters, unit cell size, volume of the unit cell, specific surface area, degree of crystallinity, dislocation density, macrostrain, and crystallinity index, were assessed using XRD data. The linear straight-line method of Scherrer's equation, Monshi-Scherrer's method, the Williamson-Hall method, the size-strain plot method, the Halder-Wagner method, and Sahadat-Scherrer's model were applied to compute the crystallite size of the synthesized HAp samples. All the synthesized HAp has crystalline structures within the permissible range of 1-150 nm which were estimated from the XRD data using the mentioned models. However, the values for strain (from -3 × 10-4 to 6.4 × 10-3), strain (from -9.599 × 104 to 7 × 1010 N m-2), and energy density (from -11 × 1011 to 2 × 107 J m-3) were also calculated for the synthesized samples. In addition, the optical band gap energy of the synthesized HAp was computed (5.89 to 6.19 eV). The synthesis media have a control on the crystallographic planes, e.g. in the case of the ethanol medium, the (110) plane exhibited significant intensity (which could potentially serve as a driving force for enhancing photocatalytic activity). The use of 100% ethanol HAp yields the most favorable outcome regarding both the degradation percentage (91.79%) and degradation capacity (7%) for the Congo red dye.

Calculation of crystallite sizes of pure and metals doped hydroxyapatite engaging Scherrer method, Halder-Wagner method, Williamson-Hall model, and size-strain plot

This research paper dealt with the synthesis and characterization of pure and metal-doped hydroxyapatite covering an in-depth crystallographic analysis. The Scherrer equation, Linear Straight-Line Model, Munshi Scherrer Model, Uniform Deformation Model, Uniform Stress Deformation Model, Uniform Deformation Energy Density Model, Size Strain Model, Halder Wagner Model, and Sahadat Scherrer Model were engaged to estimate crystallite size as well as strain, stress, and energy density from few models. All the models were evaluated with their merits and demerits along with usefulness. All the mentioned models showed acceptable results as the crystallite size ranges were from 22 to 77 nm except Linear Straight-Line Model (revealed invalid results for all the synthesized samples). The modified Williamson-Hall model (Uniform Deformation Model, Uniform Stress Deformation Model, Uniform Deformation Energy Density Model) exerted strain, stress and energy density positive and negative. But Size Strain Model, and Halder Wagner Model resulted in only positive values.

Microwave-aided fabrication of calcium-substituted DyMnO3 nanocomposites as prospective battery-type electrode material for supercapacitors

The Multifaceted properties of nanostructured rare earth perovskite manganite oxides have attracted much attention specifically for their applications in energy storage systems. In the present work, synthesis and physiochemical properties of calcium-substituted dysprosium perovskite manganite oxide nanocomposites and their potential applications as supercapacitors are examined. The perovskite structure and morphology of the designed nanocomposites are affirmed by the different analytical tools, including XRD, SEM, and TEM analysis. The structural analysis by XRD indicates the presence of DyMnO3 perovskite phase with additional peaks of Dy2O3 phase. The percentage of Dy2O3 is gradually reduced with higher Ca substitution, from about 16% to 7%. The Halder-Wagner method indicates an increase of the microstrain and a decrease in crystallite size with the rise of Ca substitution. From Tauc’s plot derived from DRS analysis, a slight increase in the band gap with the increase in Ca substitution is observed (2.55–2.62 eV). The surface elemental compositions and the valence states of individual elements analyzed using XPS analysis evidence the presence of Dy, Ca, Mn, and O. BET adsorption study indicates an increase in pore size, surface area, and pore volume with increasing Ca substitution concentration. When employed as a supercapacitor electrode material, Calcium-blend DyMnO3 nanocompositeexhibits battery type behavior. This material shows a higher specific capacitance (capacity) of 531 Fg−1 (319.9 Cg−1) with comparatively low charge transfer resistance and better cyclic stability. We have assembled an asymmetric supercapacitor device using our prepared sample exhibiting energy density of 36.16 Wh/kg with better cyclic stability. This work provides new insights for designing future Dy2O3 based supercapacitors.

Impacts of annealing temperature on microstructure, optical and electromagnetic properties of zinc ferrites nanoparticles synthesized by polymer assisted sol-gel method

Nanocrystalline zinc ferrite (NZF) were successfully synthesized at different calcination temperature via sol-gel method from the precursor salt solutions using tartaric acid and PVA solution as a chelating agent and binder respectively. The characterization of NZF and their properties had been investigated using sophisticated techniques viz. X-ray diffraction, Fourier transform infra-red spectroscopy, Scanning electron microscopy, Transmission electron microscopy, Energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, UV–Vis-NIR spectroscopy, Vibrating sample magnetometer and Impedance analyzer. X-ray peak profile analysis through Debye Scherer and Wilson method, Halder-Wagner method has been used to estimate the structural parameters. The crystallite size and particle size of ZnFe2O4 samples were found to increases with increasing annealing temperature while lattice parameters and lattice strain decreases. Dynamic light scattering and zeta potential measurements were used to evaluate the particle size distribution and stability of these systems. The room temperature magnetic properties measurement showed that the net magnetic moment is observed for NZF due to cation distribution although the bulk ZnFe2O4 is non-magnetic. Direct optical band gaps of the prepared NZF samples has been investigated by UV–Vis NIR spectroscopy using Tauc formula and found that energy band gaps (Eg) values are in a narrow range of 1.19–1.86 eV. The frequency dependent dielectric properties, impedance and modulus spectroscopy measurement has been investigated in the frequency range of 100 Hz to 20 MHz. The synthesized NZF particles will be applied for Gas sensor, humidity sensor and photocatalyst.

A Phenomenological Study of Chromium Impurity Effects on Lattice Microstrains of SnO2 Nanoparticles Prepared Using Sol–Gel Technique

In this study, the effect of chromium impurities on the crystal structure and lattice microstrains of tin oxide nanoparticles was investigated. Pure SnO2 nanoparticles were synthesized and subjected to calcination at different temperatures. Additionally, various concentrations (5%, 8%, 10% and 15%) of Cr-doped SnO2 nanoparticles were prepared using the sol–gel technique and subsequently calcined at 550 °C. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques were utilized to examine the structure and morphology of the doped nanoparticles. The XRD patterns of tin oxide nanoparticles with different percentages of chromium impurities showed a tetragonal structure without any additional phase. The TEM images of pure SnO2 nanoparticles showed a uniform distribution of size and shape, with relatively smaller sizes compared to Cr-doped nanoparticles. To investigate the peak broadening of Cr-doped SnO2 nanoparticles, the Halder–Wagner method and Williamson–Hall models were employed to examine the effects of crystallite sizes and lattice strain. The results showed that increasing the impurity has a dual effect on nanoparticle sizes. Increasing the chromium impurity up to 8% led to an increase in compressive stress caused by the substitution of Sn ions with Cr ions on the crystal structure of rutile, resulting in an increase in the magnitude of lattice strain. However, when the chromium impurity was increased up to 15%, interstitial doping was preferred over substitutional doping. The compressive stress was subsequently converted to tensile stress, requiring the system to spend some of its energy to overcome the compressive stress, with the remaining energy reflected in the form of tensile stress. Furthermore, Fourier transform infrared (FTIR) spectra were obtained for all of the samples, confirming the XRD analyses.

Determination of the crystalline size of hexagonal La1-xSrxMnO3 (x = 0.3) nanoparticles from X-ray diffraction - a comparative study.

The electronic, magnetic, optical and elastic properties of nanomaterials are governed partially by the crystallite size and crystal defects. Here, the crystalline size of hexagonal La1-xSrxMnO3 (x = 0.3) nanoparticles was determined using various methods. Single-phase La0.7Sr0.3MnO3 nanopowders were produced after 10 h of milling in a commercial high-energy SPEX 8000D shaker mill, and then they were heated at 700 °C and 800 °C to study the effect of calcined temperature on the crystallization of nanoparticles. The modified Scherrer, Williamson-Hall, size-strain, and Halder-Wagner methods were used to determine the crystallite sizes and the elastic properties, such as intrinsic strain, stress, and energy density, from the X-ray diffraction peak broadening analysis. The obtained results were then compared with one another. The difference in crystallite sizes calculated from the different methods was due to the different techniques.

Crystallographic and Physicochemical Analysis of Bovine and Human Teeth Using X-ray Diffraction and Solid-State Nuclear Magnetic Resonance.

Dental research often uses bovine teeth as a substitute for human teeth. The aim of this study was to evaluate differences in the crystalline nanostructures of enamel and dentin between bovine and human teeth, using X-ray diffraction (XRD) and solid-state nuclear magnetic resonance (NMR). The crystallite size (crystallinity) and microstrains were analyzed using XRD with the Rietveld refinement technique and the Halder-Wagner method. The 31P and 1H NMR chemical environments were analyzed by two-dimensional (2D) 1H-31P heteronuclear-correlation (HETCOR) magic-angle spinning (MAS) NMR spectroscopy. Enamel had a greater crystallite size and fewer microstrains than dentin for both bovine and human teeth. When compared between the species, the bovine apatite had a smaller crystallite size with more microstrains than the human apatite for both dentin and enamel. The 2D HETCOR spectra demonstrated that a water-rich layer and inorganic HPO4- ions were abundant in dentin; meanwhile, the hydroxyl group in the lattice site was more dominant in enamel. A greater intensity of the hydroxyl group was detected in human than in bovine for both dentin and enamel. For 31P projections, bovine dentin and bovine enamel have wider linewidths than human dentin and human enamel, respectively. There are differences in the crystallite profile between human and bovine. The results of dental research should be interpreted with caution when bovine teeth are substituted for human teeth.

Vanadium-doped CuO: Insight into structural, optical, electrical, terahertz, and full-spectrum photocatalytic properties

Aiming to widen the band gap, minimize the charge-carrier recombination, and enhance the transport properties, we reported the first synthesis of high purity vanadium-doped CuO as a promising photocatalyst nanopowder for water purification. Pure CuO and Cu1-xVxO (where x = 0.00, 0.01, 0.03, 0.05, and 0.07 mol) were synthesized by a facile sol-gel technique. The structural investigation performed by both X-ray and selected area electron diffraction patterns evidenced the formation of highly pure monoclinic CuO. The vanadium inclusion caused a noticeable red shift in Bragg's positions. The grain size was estimated by both Debye-Scherrer and Halder-Wagner methods and ranged from 21 to 28 nm. All the vibrational absorption bands disclosed by FTIR measurement are affiliated with monoclinic CuO exhibiting a small shift for V-doped nanopowders. The stoichiometry of the constituent elements (Cu, O, and V) was assured by energy dispersive X-ray analysis (EDX). The presence of agglomeration is the main feature in field emission scanning electron microscope images revealing the nanostructure property of CuO. The band gap energy of Cu0.93V0.07O determined from diffuse reflectance is 1.44 eV which meets exactly the peak of the solar spectrum rendering it a promisingly photocatalytic material. The rise of absorption in the terahertz range as measured by THz time-domain spectroscopy (THz-TDS) established the increase of density of states owing to the inclusion of vanadium. The incorporation of 0.07 mol of V considerably increases the free sunlight photocatalytic activity of CuO for high concentration Congo red pollutant (20 ppm) from 30 to 76% at the same time of 100 min (over 1.53 times as pure CuO)