Crystallite Size Research Articles

Dry reforming of methane at high temperature and elevated pressure over nickel spinellized powder catalyst and pellets prepared from a metallurgical residue

AbstractThe coke deposition on catalysts is a significant problem in the dry reforming of methane at elevated pressures. Understanding and controlling the mechanisms of such deposition is essential in developing a techno‐economically viable industrial application for the production of synthesis gas and/or hydrogen. The patent‐pending nickel‐supported upgraded slag oxide (Ni‐UGSO) catalysts, in powder form, have demonstrated excellent performance and achieved equilibrium in dry reforming, steam reforming and mixed methane reforming in a gram‐scale laboratory packed bed reactor under barometric pressure. In this extended study, Ni‐UGSO pellets were prepared using the wet impregnation method. The pelletized form of said catalyst was studied under elevated pressure to imitate the industrial operating conditions in a kilogram‐scale laboratory packed bed reactor. The characterization of the fresh and used catalytic formulation produced data allowing the investigation of the physicochemical properties of catalysts and the effects of metal dispersion, reaction pressure and crystallite size, as well as the role of side reactions on the nature of the coke. The metal support nature favored the interaction between the Ni metal and spinels (UGSO), and the presence of the clay binder (kaolinite, quartz) improved the pellet morphology, provided higher Ni dispersion, maintained the crystallite size, reduced the coke formation and achieved similar or higher performance with respect to Ni‐UGSO powder despite having 85% less surface area. The Ni‐UGSO pellet showed negligible coke deposits from 1 to 6.5 atm and operated successfully for 24 h at 5.5 atm, 800°C and gas hourly space velocity 810 L/(h kg cat). This study provides new insight into the design of a more efficient and robust catalyst for methane dry reforming at elevated pressures, which is critical for potential future transfer at the industrial level.

Study of Microstructure, Morphology and Functional Groups of Titanium Dioxide (Tio2) Impregnated With Copper (Cu)

This research aims to determine the differences in the microstructure, morphology, and functional groups of TiO2 (P-25) after being impregnated with Cu. Cu-impregnated TiO2 samples are synthesized using the impregnation method with TiO2 (P-25) and copper sulfate as precursors. The microstructure and functional groups of TiO2 (P-25) and Cu-TiO2 were investigated using X-ray diffraction (XRD), scanning electron microscope-energy dispersive x-ray (SEM-EDX), and Fourier transform infrared (FTIR) analysis. The lattice parameters (a, b, and c) of the TiO2 sample were found to be a = b = 0.3778 nm, c = 0.9494 nm, and these values increased to a = b = 0.3779 nm, c = 0.9496 nm after the addition of Cu. The distance between the lattices of the TiO2 sample was measured at 0.3505 nm and increased to 0.3509 nm after Cu addition. The average crystallite size of the TiO2 sample was 33 nm, which increased to 43 nm after Cu impregnation. The strain value decreased from 2.76×10^(-3) to 1.82×10^(-3) after Cu addition. SEM results revealed that the morphology of the particles from the Cu-doped synthesis showed agglomeration. The success of Cu doping was confirmed by EDX mapping, which showed the presence of Ti, O, and Cu evenly distributed on the TiO2 surface. The FTIR spectrum indicated that TiO2 (P-25) and Cu-TiO2 particles had absorption peaks at similar wave numbers. However, in the absorption area of 1000 cm^-1 to 1250 cm^-1, new absorption bands affiliated with Cu-O bonds appeared in the Cu-TiO2 sample, resulting from TiO2 vibrations after Cu addition.

Influence of Post-Annealing Treatment on Some Physical Properties of Cerium Oxide Thin Films Prepared by the Sol–Gel Method

In this study, thin films of Cerium Oxide CeO2 were fabricated using the sol–gel technique and deposited onto a glass substrate. The annealing process was carried out at various temperatures ranging from 200 to 600 °C to investigate the structural, morphological, and optical properties of the films and their interrelations. X-ray diffraction (XRD) patterns revealed the crystalline nature of the prepared films, with film quality exhibiting enhancement with increasing annealing temperature. The average crystallite size, dislocation density, microstrain, and lattice constant were determined from XRD patterns. Higher annealing temperatures were found to increase the crystallite size values from 4.71 to 15.33 nm and decrease the dislocation density and microstrain of the unit cell. Scanning electron microscope (SEM) images illustrated the uniformity of the films, presenting a spheroid shape. Optical properties such as transmittance, absorbance, reflectance, the direct band gap, extinction coefficients, the refractive index, and optical conductivity were assessed using optical measurements. The direct optical band gap of the CeO2 film was observed to decrease from 3.99 to 3.75 eV with increasing film thickness. Using the Wemple and DiDomenico (WDD) single-oscillator model, dispersion energy parameters were calculated based on the refractive index. The nonlinear optical properties of the CeO2 thin films were evaluated using these dispersion energy parameters. The improvement of optical parameters holds significance in standardizing CeO2 thin films for various optoelectronic applications.

Study on multifunctional magnesium copper zinc spinel ferrite nanoparticles prepared by hydrothermal route; Physical, electrical, and anti-microbial investigation

Polycrystalline spinel ferrite nanoparticles of Mg0.70-XCuXZn0.30Fe2O4(X=0.0,0.15,0.30,0.45,0.60) were prepared by hydrothermal approach. The structural modification by X-ray diffraction of Mg-Zn spinel ferrite with Cu2+ substitution was recorded through crystallite size (11–14 nm), Lattice dimension (8.34–8.38 A°), strain (7×10−3-9×10−3) and dislocation density (4×1015-7×1015) respectively. The formation of spinel structure (Fe-O) was identified by FTIR with a vibration band around 400–600 cm−1. Also, the Rietveld refined XRD pattern confirmed the presence of a cubical spinel structure. The electron microscopic (SEM) analysis revealed sphere-cubical agglomerates of the prepared material. TEM analysis revealed that the particles were inside the nanoscale range, with an average particle size of 15.97 nm determined using a lognormal histogram. The existence of the expected elements is confirmed by EDS spectra. From BET data, surface parameters including surface area (39.938–92.643 m2/gm), volume (2.355 × 10−1 to 2.52 × 10−1 gm/cm3), pore radius (5.0831–12.650 nm), and pore size distribution were determined. The magnetic parameters Ms (20–34 emu/g), Hc (30–39 Oe), and Mr (1.3–2.8 emu/g) obtained by VSM measurements indicate the single domain, pseudo single domain and multi-domain nature of as prepared nanoparticles and lower dielectric parameters at high frequency obtain from dielectric spectroscopy indicate the suitability of the material for switching devices, power application energy storage, and high-frequency applications. The antibacterial efficacy of the synthesized nanoparticles (NPs) was evaluated against different harmful bacteria and demonstrated the desired zone of inhibition (ZOI).

Evaluation of the optical and magnetic properties of novel Nd0.9Zn0.1FeO3 perovskite nanoparticles and their adsorption of Pb2+ ions from water

Nd0.9Zn0.1FeO3 was prepared in a single-phase with an average crystallite size of 25.82 nm using a citrate combustion technique. The energy dispersive X-ray assures the chemical formula of the sample. The elemental mapping of Zn-doped NdFeO3 illustrates the good homogeneous distribution of the elements in the sample. Nd0.9Zn0.1FeO3 has antiferromagnetic properties with weak ferromagnetic components and has good UV absorbance. The values of the band gap for the direct and indirect transitions are 1.473 eV and 1.250 eV, respectively. The adsorption of nickel(II), cobalt(II), chrome(VI), cadmium(II), and lead(II) ions has been studied at pH 7. The highest removal efficiency (η = 73.72%) was observed for the lead ions from water. The current study has examined the kinetics, recoveries, and mechanisms of utilizing Nd0.90Zn0.10FeO3 to remove Pb2+ ions from water. The optimum conditions for the absorbing Pb2+ are pH 7 and a contact time of 60 min. The Freundlich isotherm model is the best model for the absorption of Pb2+ ions. While, the pseudo-second-order kinetic model describes the kinetic adsorption data. The sample has a good efficiency for removing Pb2+ ions from water several times.

Structural, Morphological and Ferroelectric Properties of Sr-Cd Co-Doped Nickel Ferrite for Energy Storage Devices

Ferroelectric materials, renowned for their capacity to demonstrate spontaneous electric polarization reversible through an external electric field, are essential in numerous technological applications owing to their distinctive characteristics. For this, a series of spinel Sr-Cd co-doped nickel ferrite nanomaterials Cd0.5−xSrxNi0.5Fe2O4 (x = 0.0, 0.1, 0.2 and 0.3) were prepared through the standard sol-gel auto combustion method The XRD patterns showed that the prepared samples have a cubic spinel structure. The crystallite sizes of the samples vary from 29 to 40 nm. The morphology of prepared samples showed uniformly distributed spheres. Magnetic properties showed the soft magnetic nature of the prepared ferrites. The ferroelectric study revealed that Sr-Cd substituted ferrites exhibited the elliptical nature of ferroelectric loops at normal room temperature. The maximum polarization has been achieved at x = 0.3. The understanding of current and voltage (I–V) showed a slowly decreasing tendency of leakage current on both sides symmetrically against the increasing Sr content. The conductivity of the prepared spinel increases as a function of higher Sr doping. The real part of dielectric constant increases with increasing frequency. The materials show large elliptical loops indicating high asymmetric ferroelectric energy storage capability.

Exchange bias behaviour in cobalt ferrite-cobalt oxide CoFe2O4/CoO nanocomposites for data storage applications

Abstract In this study cobalt ferrite-cobalt oxide CFO/CoO nanoparticles were synthesized using hydrothermal chemical method for studying the exchange bias (EB) phenomena: a key parameter for data storage applications. The structural analysis was carried out by Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Energy dispersive spectroscopy (EDS), which confirm formation of platelets like CFO/CoO nanoparticles with appropriate chemical composition of different elements with an average crystallite size of 15 nm. Magnetic study revealed the ferromagnetic behaviour of nanoparticles from (5K-360K) and blocking temperature has found to be above 360 K, which decreases nonmonotonically with increasing the applied field HFC. The field cool (FC) magnetic hystersis (MH) loop studies have revealed that the samples exhibit very large exchange bias effect. The values of exchange bias (HEB) found to be maximum at low temperature and decreases with increasing temperature before vanishing at the blocking temperature. The aim of the study is to determine role of cooling field strength for the exchange bias in magnetically contrasted CFO/CoO nanoparticles suitable for data storage applications.

Enhancing surface chemistry and wetting behavior of laser-modified Ti–6Al–4V surgical titanium alloy surfaces through wet deposition of biogenic hydroxyapatite

This study focuses on enhancing the surface properties of surgical titanium alloys (Ti–6Al–4V) to optimize their suitability for biomedical implant applications. Direct laser writing (DLW) was used to modify the titanium surface and facilitate the deposition of biohydroxyapatite (BHA) particles through wet deposition and the coalescence phenomenon. Four types of etching patterns were tested, resulting in biomimetic bone-like surfaces with microtextured features, exhibiting suitable hydrophilic characteristics for biomedical implants. The resulting surfaces were characterized structurally, morphologically, chemically, and in terms of wettability. X-ray diffraction was performed to validate the titanium alloy composition and determine the crystallite size of BHA particles, both before and after thermal treatment. Optical and electron microscopy results demonstrated that the etching pattern density directly impacts the distribution and anchoring of BHA particles, with denser patterns leading to better particle fixation. Dense etching patterns were found to reduce the wettability of Ti surfaces. However, after coating with BHA particles, the contact angle decreased, resulting in more wettable surfaces. Energy-dispersive X-ray spectroscopy (EDS) mapping revealed variations in elemental distribution across different samples, providing an elemental composition analysis that supports the findings from optical and electron microscopy. The effectiveness of BHA deposition is closely tied to the density and pattern of the surface texturization. Overall, this study presents a straightforward yet effective methodology to optimize the surface properties of titanium alloys, potentially enhancing their compatibility with biological tissues.

Magnetic response of Ho3+ doped Ni0.4Cu0.6HoyFe2-yO4 spinel ferrites and their correlation with crystallite size

This study investigates the magnetic response of Ho3+ doped Ni0.4Cu0.6HoyFe2-yO4 (y = 0.0, 0.02, 0.04, 0.06, and 0.08) spinel ferrites (SFs) and their correlation with crystallite size. The synthesis was achieved using a sol-gel auto-combustion (SGAC) route and performed different characterizations, including X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy dispersive x-ray (EDX), Inductively coupled plasma atomic emission spectroscopy (ICP-AES), and vibrating sample magnetometer (VSM) analysis. The cubic spinel phase was verified via XRD in pure NCF and Ho3+ doped NCF samples. The lattice constant (a) was improved from 8.344 Å to 8.378 Å. The substitution of Ho3+ ions led to a decrease in porosity from 42.22% to 39.54%. The introduction of Ho3+ ions also reduced the crystallite size (D) from 37.05 nm to 27.72 nm. The specific surface area (S) was increased from 27.44 g/cm2 to 36.14 g/cm2 with the doping of Ho3+. The average particle size (DS) was decreased from 54 nm to 35 nm. The EDX and ICP-AES analyses confirmed the good agreement with the theoretical composition. The VSM measurements provided insights into their magnetic properties. Furthermore, the doping of Ho3+ ions enhanced coercivity (HC), while reducing saturation magnetization (MS) from 64.35 emu/g to 16.22 emu/g. The decrease in crystalline anisotropy (K) observed at higher concentrations of Ho3+ may result from the increase in coercivity, potentially attributable to the smaller crystallite size of the single-domain SFs particles. The single-phase matrix and their magnetic behaviour showed that the Ho3+ doped Ni-Cu SFs samples are suitable for high-frequency applications.

Extraction and characterization of Bougainvillea glabra fibers: A study on chemical, physical, mechanical and morphological properties

Bougainvillea glabra fibers (BGFs) present a promising avenue for sustainable material development owing to their abundance and favorable properties. This study entails a thorough investigation into the composition, physical characteristics, mechanical behavior, structural properties, thermal stability, and hydrothermal absorption behavior of BGFs. Chemical analysis reveals the predominant presence of cellulose (68.92 %), accompanied by notable proportions of hemicellulose (12.64 %), lignin (9.56 %), wax (3.72 %), moisture (11.78 %), and ash (1.75 %). Physical measurements ascertain a mean fiber diameter of approximately 232.63 ± 8.59 μm, while tensile testing demonstrates exceptional strength, with stress values ranging from 120 ± 18.26 MPa to a maximum of 770 ± 23.19 MPa at varying strains. X-ray diffraction (XRD) elucidates a crystalline index (CI) of 68.17 % and a crystallite size (CS) of 9.42 nm, indicative of a well-defined crystalline structure within the fibers. Fourier-transform infrared spectroscopy (FTIR) confirms the presence of characteristic functional groups associated with cellulose, hemicellulose, wax, and water content. Thermogravimetric analysis (TGA) delineates distinct thermal degradation stages, with onset temperatures ranging from 102.76 °C for water loss to 567.55 °C for ash formation. Furthermore, hydrothermal absorption behavior exhibits temperature and time-dependent trends, with absorption percentages ranging from 15.26 % to 32.19 % at temperatures between 30 °C and 108 °C and varying exposure durations. These comprehensive findings provide essential insights into the properties and potential applications of BGFs in diverse fields such as bio-composites, textiles, and environmentally friendly packaging solutions.

Exploring the structural, magnetic, and shielding performance of Mn doped Yb2O3 and Eu2O3 nanostructures

Re2-xMnxO3 (Re=Yb or Eu, x = 0.0, 0.05, 0.1, 0.15) nanostructures were produced utilizing the sol-gel procedure. The crystal structure and microstructure of all samples were analyzed based on XRD measurements using the Rietveld profile approach. The lattice parameter, cation distribution of different cations between different crystallographic sites, bond lengths of different polyhedrons, crystallite size, micro-strain and distortion index of the different polyhedrons of the formed sample were determined. Mn cations were found to prefer the 8b sites of the cubic bixbyite structure. The average crystallite size decreased following doping, while the microstrain experienced a significant increase. The low temperature dependent magnetizations for Yb1.85Mn0.15O3 and Eu1.85M0.15O3 nanostructures under a magnetic field of 200 Oe were investigated. Curie–Weiss law was employed to determine the magnetic configuration of the samples. The values of the effective magnetic moments μeff are 4.89 μB and 3.77 μB for Yb1.85Mn0.15O3 and Eu1.85M0.15O3, whereas the calculated values are 4.531 μB and 3.535 μB, respectively. The shielding properties of Re2-xMnxO3 (Re=Yb or Eu) nanostructures were studied using the Phy-X/PSD simulation program. The linear attenuation coefficients (LAC) and mass attenuation coefficients (MAC) values of the Yb2-xMnxO3 samples are greater than those of the Eu2-xMnxO3 samples. The half value length (HVL) and tenth value length (TVL) values increased as Mn was added to Re1.85Mn0.15O3 nanostructures. Yb1.85Mn0.05O3 and Eu1.85Mn0.05O3 nanostructures have the highest mean free path (MFP) values of 3 cm and 4 cm, respectively, at an energy of 5 MeV. The exposure build-up factor (EBF), and energy absorption build-up factor (EABF) values affected by the host rare earth oxide and the amount of Mn doping. The Re1.85Mn0.15O3 nanostructures exhibit a greater capacity to absorb photons with lower energy rather than higher energy. Yb1.85Mn0.15O3 nanostructure demonstrates exceptional neutron shielding capacities.

Impact on preferred orientation and crystal strain behavior of nanocrystal anatase-TiO2 by X-ray diffraction technique

The primary goal of this research outline is the conversion of titanium isopropoxide (TTIP) at 50.0 °C to form a high crystalline preferred oriented predominant (101) with a low crystal strain of 90.0 % anatase-TiO2 phase. With the interval of time, the peptizing agent (IP) reacts to an acidic aqueous medium and preferential growth of anatase-TiO2 has been identified. Exhaustive recombination in X-ray diffraction (XRD) analysis ensures the crystal strain, lattice volume, lattice parameters, d-spacing and crystallite size. UV–vis-NIR showed maximum absorption of 320.0 nm with 0.78 a.u. at blue shift for decreasing nano-size and smaller bandgap 3.0313 eV of larger dimensions anatase-TiO2. The preferred orientation also revealed by nanobeam diffraction (NBD) of TEM enables qualitative lattice type and highly crystal orientated predominant (101) plane 5.60 nm−1 in a diffraction pattern imposed on 200.0 kv parallel electron bean from LaB6 filament.

Structural and optical properties of In-doped CdS nanostructures: A comprehensive study

This research offers a comprehensive exploration of the effects of In-doping on the characteristics of CdS nanopowders (NPs). The structural and morphological properties of In-doped CdS nanostructures were investigated, revealing significant changes induced by In-doping. X-ray diffraction (XRD) analysis verified the formation of CdS phase. Determination of crystallite size (D) demonstrated a decrease from 27.0 nm for undoped CdS to 23.0 nm for CdS doped with 12% In-doped. Field-emission scanning electron microscopy (FESEM) imaging showed grain-like structures with sizes of 20 – 35 nm, showing variations in particle size distribution with increasing In-dopant concentration. Photoluminescence (PL) analysis illustrated changes in PL intensity and emission peak wavelengths due to In-doping. PL intensity decreased after In-doping. Additionally, a blue-shift in emission peak wavelengths indicated changes in the bandgap energy of CdS induced by In-doping. UV-Vis spectroscopy assessed the optical properties, revealing shifts in absorption and transmission spectra du to In-doping. In-doping enhanced absorption within the 400 – 500 nm range while decreasing absorption within 600 – 1000 nm. Transmission spectra displayed increased transparency after In-doping, attributed to modifications in band structure and morphology. Reflectance spectra initially increased with In-dopant concentration within 400 – 500 nm, followed by a decrease, suggesting alterations in electronic and structural properties. Estimation of band gap energy (Eg) unveiled an increase in Eg for In-doped CdS nanostructures compared to undoped CdS, likely due to reduced crystallite size and the Burstein-Moss effect induced by In-dopant ions. Raman analysis revealed a shift in peak positions and changes in intensity after In-doping, with a decrease in the 2LO/LO ratio indicating a deterioration in crystalline quality after In-doping. Overall, this comprehensive investigation provides valuable insights into the structural, morphological, optical, and electrical properties of In-doped CdS nanostructures, pivotal for their promising applications in optoelectronic devices and photovoltaics.

Structural, optical, and electrical properties of multi-component P-type oxide-semiconductor Cu-Mn-Sn-O thin films

P-type oxide semiconductors have attracted significant attention as conducting channel layers due to their wide applications in electronic devices. In this study, multi-component oxide-semiconductor Cu1–2xMnxSnxO thin films with x = 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, and 0.33 were prepared on glass substrates using a solution process accompanied by a spin-coating technique. A phase transition between the cupric oxide monoclinic structure and the rock salt structure was observed with increasing concentrations of Mn and Sn, while the concentration of Cu simultaneously decreased in the precursors. The crystallite size decreased throughout the samples, reaching a minimum value of 9.8 nm at an equimolar ratio. Scanning electron microscopy further confirmed this downward trend and indicated an improvement in the quality of the film surfaces. According to the optical absorption measurements, the bandgap energy ranged from 2.68 to 3.44 eV. Interestingly, the sheet resistance of Cu1–2xMnxSnxO films dropped sharply from 5.24 kΩ/sq for CuO to 0.034 kΩ/sq for the film with a molar ratio of Cu:Mn:Sn being 34:33:33.

Unveiling the Characteristics of MgAl0.5Fe1.5O4 Spinel Ferrite: A Study of Structural, Optical, and Dielectric Properties

Aluminum-doped magnesium ferrite (MAFO) has garnered significant interest due to its recently observed low microwave loss properties, making it invaluable for applications at high-frequency operations, including fields like spintronics and magnonics. This study delves into the optical and dielectric properties of MgAl0.5Fe1.5O4 synthesized via a conventional solid-state method followed by sintering at 1350 °C for 6 hours. The X-ray diffraction analysis confirmed the formation of pure, single-phase MAFO spinel ferrite with the lattice constant of 8.313 Å. The Williamson–Hall (W-H) method was employed to determine the crystallite size and strain from X-ray diffraction data, resulting in values of 115.4 nm and 9.37 × 10-4, respectively. UV–visible spectroscopy was used to determine the optical properties, revealing a band gap of 2.38 eV and an average refractive index of 2.09 for the investigated spinel ferrite. The dielectric properties including capacitance, dielectric constant (ε), dielectric loss, ac conductivity, complex impedance, and modulus of MAFO sample were studied as a function of frequency for various temperatures. This comprehensive analysis sheds light on the previously undiscovered traits in the material's transport phenomena and optical attributes, opening an exciting and active field of research into its other physical properties.

Enhanced photodegradation of textile dye wastewater using Silane/Polymer doped ZnO nanocomposites and antibacterial activity

Accumulation of textile dye wastewater is major global issue that causes negative impact to the ecosystem. This study focuses on industrial textile dye effluent treatment by photodegradation, and degradation of Malachite green dye under sunlight, visible and UV light. ZnO demonstrated hexagonal wurtzite structure with average crystallite size 38nm for ZnO/PEG, 21nm for ZnO/PEG/VTES and 17nm for ZnO/PEG/VTMS. Field Emission Scanning Electron Microscopy and Energy Dispersive Spectroscopy revealed nanometer sized particles and purity. Bandgap energy and particle size of ZnO/PEG/VTMS is 102nm and 3.134 eV is lesser than ZnO/PEG (147nm, 3.181 eV) and ZnO/PEG/VTES (109nm, 3.151 eV). Photoluminescence analysis revealed reduced recombination rate of ZnO/PEG/VTMS. Antibacterial efficacy of ZnO/PEG/VTMS was tested against Staphylococcus aureus (35mm) and Escherichia coli (29mm). Photodegradation of textile dye wastewater by ZnO/PEG/VTMS under visible and UV light exposure revealed an effective way for textile dye effluent treatment, which maintained its efficiency even after five photodegradation cycles.

Bound exciton engineering approach for tuning the thermal lensing phenomenon in anatase TiO2: Gd nanosystems

We report a comprehensive investigation of the third-order nonlinear interaction of femtosecond laser pulses with nanostructured anatase TiO2 doped with varying concentrations of gadolinium impurities. The samples were synthesized using a facile sol‒gel method. The physicochemical characteristics of the prepared samples were investigated using various analytical techniques, including XRD, SEM, TEM, SAED, UV‒Vis, PL and XPS. The average crystallite sizes of the pristine TiO2- and Gd (1, 2, and 3%)-doped TiO2 nanoparticles were calculated to be 10.9, 9.2, 10.2 and 8.9 nm, respectively. The W-H plots also revealed average crystallite sizes in the range of 13.9, 16.6, 13.9 and 10.4 for pristine and Gd (1, 2, 3%)-doped TiO2 nanoparticles. The lattice strain values for pristine and Gd (1, 2, and 3%) doped TiO2 nanoparticles were computed as 0.00203, 0.00667, 0.0036 and 0.00262, respectively, from the W‒H plots. The average crystallite size was calculated to 9.2 nm from the TEM images using ImageJ software. The optical band gap values of pristine TiO2 and Gd (1, 2, and 3%)-doped TiO2 nanoparticles were calculated to be 3.3, 3.23, 3.21 and 3.20 eV from the Kubelka–Munk function plot. The emission peaks of pristine and Gd(1,2,3%) doped TiO2 nanoparticles were calculated as 3.2, 3.23, 3.26 and 3.32 eV from the photoluminescence spectra recorded at 330 nm photo excitation. The binding energies of the O1s, Ti2P and Gd4d peaks present in the survey scan of TiO2 nanoparticles doped with one weight percentage of Gd impurity were 528.79, 531.53, 457.53, 463.25 and 149.6 eV, respectively. The third-order nonlinear characteristics of the TiO2:Gd samples were probed using the ultrafast laser Z-scan technique. We observed that the density of bound excitons can be regulated by controlling the dopant concentration. The strong oscillatory interactions between photogenerated bound excitons, which act as dipole oscillators with large oscillating frequencies, were recorded using a single-beam femtosecond z-scan. The third-order nonlinear susceptibility χ(3) for pristine and Gd(1,2,3%)-doped TiO2 nanoparticles were calculated as 7.258 × 10-18, 9.4 × 10-18, 11 × 10-18 and 13 × 10-18 cm2/V2, respectively. The obtained results suggest that the thermal lensing phenomenon in nanostructured anatase TiO2 can be generated and effectively controlled using a band gap engineering technique. We determined that the small pump power in nonlinear media with controllable band fluctuations can produce large phase distortions in TiO2:Gd nanosystems. Our findings reveal that Gd doping induces controlled modification of the electronic structure of TiO2, leading to a tailored energy landscape for exciton formation and binding. These findings provide a novel approach for engineering systems of TiO2-based nanostructures for energy-efficient optical-limiting nanophotonic systems and optoelectronic-switching devices.

Surface and composition effects on the biphasic cytotoxicity of nanocomposites synthesized using leaf extracts

The Malus sylvestris L. (LE1), Pinus sylvestris L. (LE2), and Sorbus aucuparia L. (LE3) leaves` extracts were used for the synthesis of silver (Ag) nanocomposites containing different amounts of silver chloride (AgCl), silver metal (Agmet), and silver phosphate (Ag3PO4). These nanocomposites were capped with the organic functional groups in the leaf extract. Notably, the nanocomposites caused biphasic cytotoxic response on cells; first attributed to the inhibition of cell growth and second to cell death. The nanocomposites were biocompatible with normal embryonic kidney (HEK293) cells in the cytotoxic range for cancer cells. LE2Ag1 [25(±1) °C synthesis] nanocomposites exhibited the highest cytotoxicity towards HeLa (lethal concentration- LC50 value of 11.4 μg mL−1) and A549 (LC50 value of 14.7 μg mL−1) after 24-h incubation and its efficiency was shown also for the more resistant MCF-7 and MDA-MB-231, however, their respective LC50 values were larger. For the HeLa cell line, this designed LE2Ag1 nanocomposite exhibited an LC50 value similar to the effective concentration (EC50) value of Cisplatin and about 3 times larger than Doxorubicin. LE2Ag1 nanocomposite contained Ag3PO4 in the composite and P on the surface, higher AgCl content, smaller crystallite size of all nanoparticle phases, and carbon-rich oxygen-deficient surface compared to all other nanocomposites.

Impact of Gd-Substitution on Structural, Dielectric, Spectroscopic, Raman, and Photo luminance Properties of Ba0.4Sr0.6Co2Fe16O27 Ceramics

This paper represents a detailed study of Gd3+ substitutions on Structural, Dielectric, Spectroscopic, Raman, and Photo luminance Properties of Ba0.4Sr0.6Co2Fe16O27 magnetic oxides were prepared using the sol-gel auto combustion method. All of these specimens were sintered at 1100 ºC for five hours. X-ray diffraction analysis (XRD) confirmed the single-phase detection and structural analysis. The lattice parameters a and c show the insignificant behavior 5.893-5.933 Å, and 32.049-32.476 Å with the concentration of gadolinium ions. The crystallite size ranged from 25 to 30 nm, demonstrating a growing tendency as Gd-substitution was enhanced. The discrepancy in the ionic radii of iron (Fe3+) and substituent elements (Gd3+) is the cause of the variation in cell volume and lattice constants. FTIR spectroscopy confirmed the presence of absorption bands (590 and 3000 cm-1) for prepared BaSr-based W-type hexa-ferrites. The vibrational bands of metal oxide ions are responsible for the 590 and 685 cm-1 peaks. The Raman spectrum showed six discrete, brittle peaks: 320, 440, 620, 690, 1300, and 1600 of synthesized nanomaterials—the dielectric constant and dielectric loss increase by substituting the Gd3+ ion. The dielectric parameters and dielectric loss at higher frequencies suggest that the prepared material may be excellent for switching, sensing, and high-frequency applications.

Investigating the Influence of Cerium Doping on the Structural, Optical and Electrical Properties of ZnNiMgFe2-xCexO4 Soft Ferrites

The present work reports the optical, structural, and electrical properties of cerium-doped Zn0.6Ni0.2Mg0.2Fe2-xCexO4 soft ferrites by green synthesis method that unwrap transformative insights and find technological applications through X-ray diffraction (XRD), UV visible spectroscopy and IV-point probe techniques. Ferrites with different cerium concentrations (x = 0.0, 0.0250, 0.0375) show an enormous difference in the optical, structural, and electrical behavior of the ferrites. The crystallite size increases to 46.9 nm, with a concomitant increase in lattice constants up to 8.550 Å for x = 0.0375. A similar structural shift was noticed in X-ray and bulk densities from 5.031 to 4.982 g/cm³ and 3.83 to 3.97 g/cm³, respectively. The optical explorations revealed a remarkable bandgap reduction from 2.72 eV to 2.06 eV improving the utility of the material substantially in magneto-optic devices. Conversely, the refractive index increases from 2.431 to 2.605, and the imaginary dielectric constant goes up from 10.692 to 11.228, giving a herald of advancement in photonic technologies. Electrically, the study marks a drastic reduction in DC resistivity from 6.15×105 to 9.71×108 ohm-cm with the Ce doping, which indicates higher conductivity suitable for telecommunication. This extensive work on Ce-doped soft ferrites now opens up newer avenues of applications in electronics and magneto-optics, blending scientific inquiry with practical utility.