Williamson-Hall Method Research Articles

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.

Crystal structure modification of nano-hydroxyapatite using organic modifiers and hydrothermal technique.

Hydroxyapatite (HAp) synthesis was achieved through a hydrothermal method involving orthophosphoric acid and calcium hydroxide. Different organic modifiers such as urea, naphthalene, and palmitic acid were applied in the reaction system to modify the crystallite size along with the morphology of HAp. The synthesized HAp was validated via X-ray diffraction (XRD) data, Fourier Transform Infrared (FTIR) spectra, Field Emission Scanning Electron Microscopy (FESEM) image, and optical bandgap energy (<6 eV) was determined through UV-vis spectrophotometry. Apart from that, different techniques such as Scherrer's method, Halder-Wagner model, Williamson-Hall method, size-strain plot, as well as Sahadat-Scherrrer's models were applied for calculating the crystal domain size, and some models also incorporated energy density, strain, and stress. The synthesized HAp has a crystal structure that falls within the permissible range of <100 nm, as established by analyzing the XRD data using established models. Nevertheless, the values for strain (from -0.0006 to 0.0062), stress (from -30 902 to 36 940 N m-2), as well as energy density (from 4 × 10-14 to 113.72 J m-3) were likewise computed for the synthesized HAp. The texture co-efficient analysis reveals that doped HAp is grown in the (202) and (112) planes, palmitic acid_HAp in (002), (112), and (202) planes, while all the synthesized HAp (pure HAp, urea, naphthalene) is grown in the (002) and (112) planes. Rietveld refinement was also performed to estimate the quantative phase percentage from XRD data.

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.

A detailed investigation of rare earth lanthanum substitution effects on the structural, morphological, vibrational, optical, dielectric and magnetic properties of Co-Zn spinel ferrites.

In this work, Co0.5Zn0.5LaxFe2-xO4 (0.00 ≤ x ≤ 0.10) spinel ferrites were synthesized using the sol-gel auto-combustion method. X-ray diffraction (XRD) analysis and Rietveld refinement confirmed the presence of a cubic spinel structure. The crystallite size was estimated to be between 17.5nm and 26.5nm using Scherrer's method and 31.27 nm-54.52nm using the Williamson-Hall (W-H) method. Lattice constants determined from XRD and Rietveld refinement ranged from (8.440 to 8.433Å and 8.442 to 8.431Å), respectively. Scanning electron microscopy (SEM) revealed a non-uniform distribution of morphology with a decrease in particle size. The bandgap values decreased from 2.0eV to 1.68eV with increasing rare earth (La3+) doping concentration. Fourier-transform infrared (FT-IR) spectroscopy confirmed the presence of functional groups and M-O vibrations. The dielectric constant and dielectric loss exhibited similar behavior across all samples. The maximum tan δ value obtained at lower frequencies. Regarding magnetic behavior, there was a decrease in magnetization from 55.84 emu/g to 22.08 emu/g and an increase in coercivity from 25.63Oe to 33.88Oe with higher doping concentrations. Based on these results, these materials exhibit promising properties for applications in microwave and energy storage devices.

Investigating Fe-doped Ba0.67Ni0.33Mn1-xFexO3 (x = 0, 0.2) ceramics: insights into electrical and dielectric behaviors.

This study investigates the characteristics of the Ba0.67Ni0.33Mn1-xFexO3 perovskite compound, focusing on its structural and electrical aspects under varying Fe doping levels at the Mn-site (x = 0, 0.2). X-ray diffraction patterns confirm the material's consistent structure, with Fe3+ ions substituting Mn3+ ions while maintaining their identical ionic radius. Nano-crystallinity studies reveal single-phase crystallization in the orthorhombic structure with space group Imma. Samples are prepared through conventional solid-state sintering. The Williamson-Hall method calculates crystallite sizes, averaging 37 nm for x = 0 and 33 nm for x = 0.2. Electrical properties are examined using complex impedance spectroscopy at different temperatures and frequencies. Techniques such as energy dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM) assess chemical composition. Activation energy values increase from 0.138 eV for x = 0 to 0.171 eV for x = 0.2, leading to reduced dc conductivity across the investigated temperature range. Dielectric permittivity enhances proportionally with increasing Fe doping. Variations in impedance profiles reveal a relaxation phenomenon. A circuit model, Rg + (Rgb//CPEgb), elucidates impedance data. This study illuminates the interplay between Fe doping, activation energy, and electrical conductivity in Ba0.67Ni0.33Mn1-xFexO3 perovskite, offering insights applicable to electronic and energy-related devices. Perovskite-based nanomaterials have diverse environmental applications, including solar cells, light-emitting devices, transistors, sensors, and energy storage.

Magnetoelectric behaviour of Pb-free Na0.5Bi0.5TiO3-Ni0.5Co0.5Fe2O4 particulate novel ceramic composites

Magnetoelectric (ME) multiferroic composites are more promising candidates for low-power consumption devices, next-generation spintronic devices, and multistate memory devices since they exhibit significantly higher Magnetoelectric interaction over single-phase multiferroics. In this regard magnetic behaviour, dielectric, and magnetoelectric characteristics of a novel Pb-free (1-x) Na0.5Bi0.5TiO3-(x) Ni0.5Co0.5Fe2O4, (x = 0, 0.2, 0.4, 0.6, 0.8 & 1) particulate composites were explored. Solid-state synthesis was adopted to prepare the single-phase Na0.5Bi0.5TiO3 (NBT), Ni0.5Co0.5Fe2O4 (NCFO), and their composites. The presence of rhombohedral NBT and cubic inverse spinel NCFO in the composites were confirmed with X-ray diffraction (XRD) patterns. Microstrain (ε) induced in the prepared samples was estimated by using the Williamson-Hall (W-H) method. The piezoelectric NBT phase shows the tensile strain and the ferromagnetic NCFO shows the comprehensive strain. Among all the composites 0.8NBT-0.2NCFO shows a higher strain value of 0.012%, and the decrement in the strain values was observed upon increases in ferrite concentration. Backscattered scanning electron microscope (BS-SEM) images revealed the existence of highly dense uniformly distributed elements and Energy dispersive spectroscopy (EDS) confirmed the existing elements in the composites. UV–vis absorbance spectra disclosed a rise in energy gap values from 1.14 eV to 3.0 eV with increasing NBT percentage. Variations of dielectric permittivity and dielectric loss with respect to AC frequency were studied at room temperature (RT), and the 0.2NBT-0.8NCFO sample shows a high dielectric permittivity of 8500 at ∼100Hz. M − H (Magnetization-Magnetic field) hysteresis loops demonstrate the pure ferrite phase has a coercive field (Hc) = 578 Oe, remnant magnetization (Mr) = 21.43 emu/g and saturation magnetization (Ms) = 71.29 emu/g. The Ms and Mr values in the composites are enhanced with increasing ferrite percentage. Studies on ME behaviour of (1-x) NBT-(x) NCFO, (x = 0.2,0.4,0.6 & 0.8) show the coupling effect between both the phases at room temperature and the highest coupling coefficient value 3.16mV/Cm. Oe was observed for the 0.8NBT-0.2NCFO further the reasons and mechanisms are discussed.

Quantitative Determination of the Compositional Inhomogeneity in NMC Cathode Materials by Williamson-Hall Analysis

Over the past decades, the co-precipitation synthesis technique has been used, particularly for making LiNixMnyCozO2 (NMC) cathode materials for lithium-ion batteries (LIBs), due to better control of particle morphology and higher compositional homogeneity in the final NMC product compared to other methods. However, the co-precipitation method introduces complexity and consumes large amounts of energy and water, which can increase cost. This has led researchers to investigate solid-state NMC synthesis techniques in order to improve sustainability and reduce LIB cost [1-3]. Obtaining homogeneous mixing of transition metals at the atomic scale by solid-state methods remains a challenge. Since compositional homogeneity has a vital effect on the electrochemical performance of the NMCs, it is essential to quantitatively estimate the degree of inhomogeneity in cathode materials for the development of new synthesis methods.In the present study, a quantitative X-ray diffraction (XRD) analysis technique using the Williamson-Hall (WH) method is used to determine the degree of inhomogeneity in NMC precursors and NMC cathode materials. In this regard, single-phase rock salt (RS) precursors with varying degrees of transition metal homogeneity were prepared by combining NiO, MnO and CoO by grinding for different times, followed by heating under an Ar flow. Then, NMC cathode materials were made by heating the RS-precursors with lithium carbonate in air. EDS elemental maps showed that transition metal inhomogeneity existed in the RS-precursors and final NMCs and that this inhomogeneity is primarily associated with the Mn distribution (Figure 1(a)). Furthermore, the compositional inhomogeneity became reduced with increasing precursor grinding time.Using a WH analysis method, composition variation in the NMC precursor and in the final NMC product could be quantitatively determined from conventional XRD powder patterns. Utilizing this analysis, it was found that inhomogeneity in the precursor is translated into the final NMC, so that a similar trend in the degree of inhomogeneity was observed for both synthesized precursors and their NMC products (Figure 1(b) and (c)). Additionally, NMCs with high compositional homogeneity showed much better electrochemical performance compared to the samples with higher degree of inhomogeneity. We believe the proposed method is highly useful in the development of new cathode precursors and in predicting the performance of the NMC cathode materials by quantitatively determining their degree of compositional inhomogeneity.

Formation of PbS microstructured films by CBD method and study of structural properties

Microcrystalline lead sulfide (PbS) films were synthesized using the chemical deposition method. The films were deposited on pre-cleaned glass substrates and polished silicon wafers. Chemicals of high purity were utilized in the process. The morphology, composition, and structure of the films were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The films exhibited a galena phase with a face-centered cubic structure belonging to the Fm-3m space group. The average grain size was determined using the WilliamsonHall method, revealing a homogenous structure. Raman spectroscopy further confirmed the structural integrity of the films. The obtained results contribute to the understanding of the synthesis and properties of microcrystalline PbS films.

Investigations of the structure and tunable magnetic properties of Cu doped cobalt chromite nanoparticles

This article reports the synthesis, microstructural, magnetic and optical properties of copper ions substituted cobalt chromite nanoparticles. We have prepared four nanosized chromite samples with a general composition of CuxCo1-xCr2O4 (x = 0.0, 0.1, 0.2 and 0.3) using conventional wet chemical co-precipitation method. The x-ray diffraction profiles verified the presence of pure spinel crystal structure of the samples. Using the Williamson-Hall (W-H) method, the average crystallite size of all the samples were calculated to be between 11 nm and 16 nm. A tensile microstrain in all the samples was noticed. Surface morphology and average particle size of doped cobalt chromite nanocrystals was examined using HRTEM images. A moderate increment in the optical band gap was detected with increasing Cu ions in cobalt chromite nanoparticles which is attributed to the nanosize effect of the samples. The presence of all five distinctive Raman active modes in the chromite samples ensured phase purity and a decrease in crystal symmetry was also observed as the amount of Cu dopants was increased. Due to low magnetic moment of Cu2+ ions when compared with Co2+ ions, incorporation of copper ions reduces the coercive field of the host chromite system. With increasing Cu percentage in chromite especially for 30 % Cu doped sample, the spin-spiral transition TS vanishes which indicates TS is affected by the dopant concentrations.

Influence of rare-earth elements (RE = Ce, Nd, Gd) on structural, ESR and Mössbauer spectroscopy studies of Ni0.5Co0.5RE0.03Fe1.97O4 synthesized by glycol-thermal method

Nanocrystalline Ni0.5Co0.5RE0.03Fe1.97O4 (RE = Ce, Nd, Gd) were synthesized by glycol-thermal method. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results confirm the formation of single-phase spinel ferrite. The crystallite sizes ranged from 6.29 nm to 9.41 nm which was comparable to results obtained using Williamson-Hall (W–H) method. Lattice parameters were found to vary from 8.356 Å to 8.370 Å depending on an ionic radii of a substituted rare-earth elements. Large specific surface areas ranging between 120 m2/g and 160 m2/g were associated with smaller crystallite sizes. Scanning electron microscope (SEM) revealed homogeneous and clustered nanoparticles. The energy dispersive X-ray (EDS) spectra revealed the existence of nickel (Ni), cobalt (Co), iron (Fe), and oxygen (O) in an undoped sample. The additional characteristic peaks of cerium (Ce), neodymium (Nd) and gadolinium (Gd) were observed for doped samples. The electron spin resonance (ESR) results demonstrated g-values ranging between 3.10 and 3.79 which indicated strong exchange interaction between nanoparticles, type of morphology, and crystalline nature of particles. These high g-values make Ni0.5Co0.5RE0.03Fe1.97O4 (RE = Ce, Nd, Gd) materials suitable for applications in high-frequency devices. The Mössbauer spectroscopy results revealed the formation of broadened Zeeman lines and quadrupole-split lines as well as the presence of the Fe3+ ions at B sites in the samples.

Facile fabrication and grain-size depended on structural behavior of Cadmium-Substituted nano Co-Ni ferrites by chemical method

In this work, cadmium doped cobalt nickel ferrites were fabricated via co-precipitation method by using high purity chlorides as precursors and ammonia as precipitate. XRD measurements of synthesized Co0.6Ni0.4-xCdxFe2O4 ferrite samples revealed that the formation of mono phase cubic spinel structure ferrite nanoparticles. The volume of unit cell, crystallite size, lattice constant, bond length, hopping length, ionic radii and microstrain were directly affected by the inclusion of Cd2+ content in Co-Ni ferrite. The crystallite size (Dxrd) of prepared ferrite samples was obtained in between 14.52 and 16.92 nm. FTIR spectra showed two main absorption bands in the frequency range of 400–600 cm−1 arising due to stretching vibrations of tetrahedral (A) and octahedral (B) sites respectively. SEM analysis showed agglomerated morphology of ferrite nanoparticles with grain size decreased from 0.85 to 0.21 μm. Raman spectroscopy confirmed that, on addition of Cd2+content, Raman band was shifted towards higher wave number side. The crystallite development in Cd doped Co-Ni ferrites was explored by X-ray peak broadening methods such as Scherer’s formula, Size-Strain plot and Williamson hall methods. XRD analysis confirmed, the crystallite size and microstrain of Co0.6Ni0.4-xCdxFe2O4 ferrites were obtained from various methods, are highly inter correlated. Saturation magnetization (Ms) was decreased from 29.92 to 23.40 emu/gm with increase of Cd doping. The coercivity was reduced from 1113 to 708 Oe with Cd concentration. This is due to the magnetic anisotropy constant of Ni2+ ion is higher than that of the Cd2+ ion.

Wrinkle type nanostructured of Al-Ce co-doped ZnO thin films for photocatalytic applications

ZnO:Al:Ce thin film photocatalysts were prepared by sol-gel spin coating method for the photocatalytic degradation of Methylene Blue (MB). The effect of Al-Ce co-doping on the structural, surface, optical and photocatalytic properties of ZnO films was analyzed. The crystallite size of the films calculated using the Williamson-Hall method decreased with Al-Ce co-doping. The enhanced photocatalytic activities of ZnO:Al:Ce wrinkle type nanostructured films can be associate with the increased surface area due to the crystallite size reduction by the Al-Ce co-doping. In the morphology analyzes of the films, the wrinkle network structure was observed in the pure ZnO and (6 %) Al-Ce co-doped ZnO films. All ZnO:Al:Ce films exhibited high transparency in the visible light (> 90%). Photoluminescence (PL) spectra depict near band edge (NBE), violet, blue, blue-green and green emission in deposited films. The photocatalytic test shows that the presence of Al-Ce enhances MB degradation efficiency up to 94 %. As a result, it has been observed that the co-existence of Al and Ce has significant effects on both the physical and photocatalytic properties of ZnO films.

Mg-modified Zn-Co-Fe-La nano ferrites: A study of structural, morphological, vibrational, electro-optical, dielectric and magnetic evolution

The series of Zn0.4Co0.6−xMgxFe1.9La0.1O4 (x = 0.0, 0.15, 0.30, 0.45, 0.6) nanoferrites prepared via co-precipitation technique. Scherrer and Williamson-Hall (W-H) methods were used to find the crystallite size (29.6–39.2 nm and 31.6–36.3 nm, respectively) and lattice constant was calculated (8.406–8.395 Å). Moreover, Fourier transform infrared (FTIR) spectroscopy revealed the existence of absorption bands along with functional groups. The vibrations of O2- ions at the tetrahedral and octahedral sites were shown by the Raman five active modes. DC resistivity reduced in the range of 5.2961 × 108 Ω cm to 9.6453 × 107 Ω cm for x = 0.0 to x = 0.6, respectively. The maximum DC resistivity and activation energy (0.1035 eV) were obtained at the parent sample (Zn0.4Co0.6Fe1.9La0.1O4). The optical bandgaps reduced from 2.61 to 1.47 eV, as the Mg2+ contents increased. With increasing frequency the dielectric loss and the dielectric constant decrease. The magnetic parameters such as saturation magnetization (Ms= 60.82–25.94 emu/g), remnant magnetization (Mr = 47.82–18.64 emu/g), and coercivity (Hc = 1334–511 Oe) demonstrated reducing trends with the increase of Mg2+ doping. The best magnetic behavior of the as-prepared samples suitable in microwave devices was observed for Zn0.4Co0.6Fe1.9La0.1O4 sample.

Unveiling the effect of strain engineering on the electrochemical properties of hydrothermally grown nanostructured indium doped ZnSeO3 for photoanode applications

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 (DRS), photoluminescence (PL) spectroscopy, and Thermogravimetric Analysis (TGA). The structural analysis indicates that all patterns are assigned to the ZnSeO3 orthorhombic structure. Also, XRD analysis shows that In3+ ions may have replaced Zn2+ ions, which causes lattice expansion. Both the Debye–Scherrer method, and the Williamson–Hall method have also been applied to study the influence of strain on the calculation of the crystallite size. The crystallite size was observed to increase with an increase in dopant concentration. The FE-SEM corroborated that the prepared samples are orthorhombic, with the EDS and mapping confirming the presence of In as a dopant. Raman spectroscopy results corroborated the XRD results indicating an expansion in the crystal structure of ZnSeO3 with the introduction of dopants. Based on DRS data, the introduction of In decreases the energy band gap of the synthesized ZnSeO3 nanopowder samples from 3.305 to 3.276. PL spectra confirm the presence of indium with the green emission band attributed to dopants dominating the emission. The TGA investigation shows an improvement in the mass loss with the introduction of dopants. EIS results indicated an improvement in the conductivity as the charge transfer resistance decreased from 525.04 to 21.95 kΩ for the undoped ZnSeO3 and 0.75% In–ZnSeO3 thin films showing improvement in charge mobility.

S-scheme heterojunctions based on novel Sm2CeMnO6 double perovskite oxide and g-C3N4 with excellent photocatalytic dye degradation performances.

It has become of utmost importance to preserve marine life and human health by protecting aquatic environments from contaminants. Therefore, using photocatalytic materials in treatment of contaminated water is a promising and innovative technique. Novel double perovskite Sm2CeMnO6 was synthesized through a modified Pechini sol-gel method. Also, urea and melamine were utilized to synthesize graphitic carbon nitride (g-C3N4). Combination of Sm2CeMnO6 and g-C3N4 produced several S-scheme heterojunction materials in diverse components ratios. Average crystallite sizes of Sm2CeMnO6 and Sm2CeMnO6/g-C3N4 (20:80) samples were calculated by Debye-Scherrer and Williamson-Hall methods to be 19.77, 22.72 nm and 42.01, 43.73 nm, respectively. The coexistence of g-C3N4 (002) with a d-spacing of 0.325 nm and Sm2CeMnO6 planes of (222), (111), and (400) with spacing values of 0.314, 0.302, and 0.294 nm, respectively, was depicted in the HR-TEM image of the Sm2CeMnO6/g-C3N4 (20:80). The estimated bandgaps for the g-C3N4, Sm2CeMnO6, and Sm2CeMnO6/g-C3N4 (20:80) were 2.70, 2.60, and 2.65eV, respectively. Their application was investigated in photocatalytic degradation of methylene blue (MB) dye as typical pollutant. The estimated degradation pathway of MB was also provided through LC-MS analysis. Under the identical conditions, the best photocatalytic performance was found for Sm2CeMnO6/g-C3N4 (20:80) composite. Using response surface methodology (RSM), operational parameters of the photocatalytic degradation were modeled and optimized by the best composite through central composite design approach. Applying optimized parameters led to 96% degradation of MB (8 mg/L) at pH 10 under 120 min visible light irradiation (λ > 365 nm) using 0.15 g of Sm2CeMnO6/g-C3N4 (20:80) composite in 100 mL aqueous solution. Due to low intrinsic charge transfer resistance, modified Eg, and good performance in e‒/h+ pairs production, Sm2CeMnO6/g-C3N4 (20:80) nanocomposite was introduced as a promising S-scheme photocatalyst.

Fullerene (C60)‐doped zinc‐aluminium layered double hydroxide/polyvinyl alcohol nanocomposites: Synthesis, characterization, and photodegradation of methylene blue from water solution

AbstractIntroductionLayered double hydroxides (LDHs) are widely studied anionite clays consisting of positively‐charged hydroxide nanosheets which is described by the general formula: [M(II)1−xM(III)x(OH)2][An−·mH2O], where M(II) and M(III) are the divalent (e.g., Mg2+, Zn2+, Ca2+, Co2+, Ni2+, etc.) and trivalent (e.g., Al3+, Fe3+, Cr3+, etc.) metal ions, An− and H2O is the interlamellar anion (e.g., Cl¯, Br¯, NO3¯, CO32¯, SO42¯, SeO42¯) for charge‐neutralization and hydrated state, respectively. They have been widely used in different industry sectors, in materials science and research. Polymer/LDH nanocomposites have gained significant attention in recent years.Carbon‐based nanomaterials, like fullerene, carbon nanotubes (CNT), graphene and graphene oxide have attracted significant attention. Fullerene molecules (C60, C70) are used as reinforcing material for polymers to improve their mechanical, thermal, optical, energy storage and charge transport properties.ObjectivesC60‐doped ZnAl‐layered double hydroxide/polyvinyl alcohol nanocomposites were successfully synthesized and their photocatalytic activity for photodegradation of methylene blue (MB) synthetic dye was quantitatively analyzed by ultraviolet (UV) spectroscopy. The effect of C60 on the optical, structural, morphological properties, and photocatalytic activity of LDHs was investigated, and the impact of C60/LDH mass ratio and aging time on the properties was also studied.MethodsFullerene‐doped ZnAl‐LDH/PVA nanocomposites were synthesized via urea hydrolysis and coprecipitation‐coformation method. First, 10 wt% PVA/water solution (40 mL) is added into the mixed solution containing 0.015 mol of Zn(NO3)2·6H2O and 0.005 mol of Al2(SO4)3·9H2O and titrated by 2 M of NaOH and 1 M of NaHCO3 mixed base solution to adjust pH 9. The obtained white slurry was shaken very hard and aged for 1 year. The obtained samples were marked by the mass percentage of C60 as 1% C60@LDH/PVA, 10% C60@LDH/PVA, 20% C60@LDH/PVA, and 60% C60@LDH/PVA.Results and DiscussionThe basal spacing of C60‐doped ZnAl‐LDH was estimated to be 9.217 Å which is wide enough from the general LDH (~7.0 Å). The crystallite size of nanoparticles is 9.217 nm and ~6 nm by Scherrer's equation and Williamson–Hall method from the XRD data, respectively. Rice‐shaped 2D morphology was formed with 100 nm–2 μm width and 500 nm–10 μm in length by SEM. The maximal photodegradation efficiency was found with 20% of C60 doping (PD% = 96.98) after 360 min, where the sorption efficiency with this compound is very high (R% = 85.55).ConclusionsIn the presented work, the effect of C60 on the optical, structural, morphological properties, and photocatalytic activity of LDHs was investigated, and the impact of C60/LDH mass ratio and aging time on the properties was also studied. For the identification of the photocatalytic activity of obtained C60/LDH nanocomposites, MB was used as a model pollutant and the efficiency of the Zn/Al LDH nanocomposite, with various quantities of fullerene, is also evaluated.

Simple single reactor synthesis of nickel (II)-cobalt (II) ferrite composites with biochar and their photocatalytic properties

The paper proposes a simple one-stage synthesis of ferrite/biochar composites based on oxide compounds of NixCo1-xFe2O4 (х = 0, 0.5, and 1). The obtained materials were characterised using x-ray diffraction patterns, Fourier transform infrared (FTIR) spectrometry, electron microscopy, Scherrer and Williamson-Hall methods. The high photocatalytic activity of the synthesised materials in the process of methyl orange oxidative degradation at hydrogen peroxide presence has been established. It is noted that the highest catalytic activity is exhibited by the composite material based on cobalt (II) ferrite and sunflower biochar: in their presence, it is possible to achieve 100% removal of the dye after 120 and 90 min, respectively. A possible mechanism of the dye decomposition process is discussed.

Photocatalytic evaluation of synthesized MnO2/Fe3O4 NCs by Q. infectoria extract for removal Ni(II) and phenol: Study phytochemical, kinetics, thermodynamics, and antibioactivity

In the present study, the plant extract of the Quercus infectoria galls was used as a reducing, capping, and stabilizer agent for green synthesized MnO2 nanoparticles (NPs) and MnO2/Fe3O4 nanocomposites (NCs) due to its reduction ability from polyphenol and antioxidant content. The green synthesized nanomaterials have been characterized by various techniques such as FTIR, UV–vis, XRD, SEM, EDS, and TEM. The average size of about 7.4 and 6.88 nm was estimated for the NCs crystals of SEM images and XRD analysis by the Scherrer and Williamson-Hall methods. The green synthesized MnO2/Fe3O4 NCs (dosage: 0.1 g) have shown high photocatalytic activity for the removal of Ni(II) in acidic and basic solutions under visible irradiation (220 V lamp). The removal efficiency for the Ni(II) solution (3.6 × 10−3 M) at pH = 3 was increased to pH = 12 from 56 % to 98 %. The oxidase-like activity of MnO2/Fe3O4 NCs at different dosages (0.05, 0.1, and 0.15 g) for the removal and colorimetric of phenol (1 g/40 mL) in the presence 4-AAp (1 g) was seen after only 28, 13, and 5 s, respectively. The kinetic evaluation results showed the pseudo-second-order kinetics model closely matched the adsorption capacity theoretical values qe,cal (578.03, 854.70, 892.85, and 917.43 mg.g−1) and experimental values qe,exp (521.84, 839.74, 887.86, and 913.22 mg.g−1) at different initial pH solution (3−12) for Ni(II) removal. In addition, the investigation of isotherm models revealed that the Langmuir model (R2 = 0.9955) explains a better estimate for a monolayer and favorable removal of Ni(II) ions onto NCs. Also, the low Temkin constant, BT < 0 (0.0200 kJ.mol−1), and positive ∆H° value (0.103 kJ.mol−1.K−1) illustrated that Ni(II) removal is physical sorption and endothermic process. However, the obtained thermodynamic results showed the negative values ΔG° with the increase in temperature (303–318 K) toward a spontaneous removal process of Ni(II). Finally, the plant antioxidant (200 to 3200 μg/mL) and antimicrobial activities (0.001 to 0.1 g/mL) for plant extract, MnO2 NPs, and MnO2/Fe3O4 NCs were evaluated against Gram-positive and Gram-negative bacteria species.

Complex impedance spectroscopy, dielectric response, and magnetic properties of the La0.7 Sr0.3BO3 (B = Mn, Fe, Co, or Ni) perovskite oxides

The perovskite materials (La0.7Sr0.3BO3, B= Ni, Co, Fe, or Mn), in the present study, have successfully been prepared, using the co-precipitation method. X-ray diffraction data confirmed the multiphase structures in all synthesized samples except in lanthanum strontium ferrite. With the help of the Williamson-Hall method, based on the uniform deformation model, the strain and crystallite size of the synthesized samples have been calculated. The maximum crystallite size and minimum strain are observed in the lanthanum strontium ferrite sample. In addition, the obtained structural data help us to calculate the texture coefficient. Field emission scanning electron microscope images prove the formation of the nano-scaled particles. Moreover, the energy-dispersive X-ray analysis confirm the formation of lanthanum strontium-based perovskites that are synthesized in this project. Fourier transform infrared spectroscopy spectra represent the metal-oxide bonds in the 495 cm−1, 592 cm−1, 577 cm−1, and 622 cm−1 for LSNO, LSCO, LSFO, and LSMO, respectively. The examination of the dielectric properties of synthesized nanoparticles at room temperature has been conducted in great details across a range of frequency range of 10−3 Hz to 1 MHz. The capacitance of all samples demonstrates an increase as frequency decreases. Moreover, the obtained results validate that the dielectric parameters exhibit an increase with frequency decreasing for all samples. The outcomes of the Modulus exhibit an increase in the vicinity of high frequencies, whereas the magnitudes of the Modulus tend to converge toward zero in the proximity of low frequencies. Contrary to the effect of nickel, cobalt, or Iron substitution for manganese in dielectric parameters values, the magnetic parameters, denoted by μ′andμ″, of lanthanum strontium manganite prove to be smaller than the magnetic parameters of other synthesized samples. A VSM at room temperature reveal the LSMO and LSCO samples to be paramagnetic and the LSFO and LSNO samples to be ferromagnetic.

SYNTHESIS OF NICRALX MICROPARTICLES USING DRY MILLING AND WET MILLING PROCESSES

The characteristics of synthesized NiCrAlY and NiCrAlZr composite powders produced by the milling process were investigated to understand the particle size, the shape of particles, and the properties of crystalline structure. The milling process was carried out by combining dry milling with the wet milling method to prevent agglomeration, produce a homogeneous alloy powder, and reduce the particle size. Ethanol was used during the wet milling process as a process control agent. The PSA (particle size analysis) showed that the particle size was effectively reduced from ±70 μm to less than 30 μm. In addition, surface structure analysis characterized by SEM (scanning electron microscope) revealed that particle shape changed from blocky particles after dry milling into flaky, flattened, and fragmented particles after wet milling. An XRD (x-ray diffraction) was used to identify the phases of powders before and after the mechanical milling process. Crystal structure analysis was calculated from the change of peak broadening in XRD peak spectra. The Williamson-hall method has been performed to calculate the strain and crystallite size of synthesized NiCrAlY and NiCrAlZr composite powder in the present study. The findings in this study show the characteristics of powders, which are important information for producing coatings with good performance.