Metal Oxide Bonds Research Articles

Luminescence and dielectric investigations of crystalline niobate nanoceramics prepared through aqueous chemical process

The present study reflects the synthesis of MgNb2O6 using hydrofluoric acid via a wet chemical approach, followed by characterizations involving XRD, electron microscopy, Raman spectroscopy, optical analyses, and impedance spectroscopy. The crystallite size of the synthesized material was determined to be 44 nm through XRD analysis. The lattice parameters of MgNb2O6 a, b, and c, were found to be 14.1998 Å, 5.6844 Å, and 4.9813 Å, respectively. Raman spectroscopy identified molecular bonds ranging from 253 to 1011 cm−1, mainly indicating the presence of metal oxide bonds. EDX spectra confirmed the presence of Mg, Nb, and O atoms in the prepared ceramics, indicating phase purity. FESEM analysis revealed a grain size of approximately 48 nm, with the presence of agglomerated grains. Bright spots in the SAED pattern observed by HRTEM confirmed the crystallinity of the prepared niobate materials, with the HRTEM microstructure showing a particle size near 49 nm. The crystallite size by XRD, grain size by FESEM, and particle size by HRTEM are in accordance with each other. The direct band gap was determined to be approximately 2.76 eV using UV-Visible spectroscopy. Additionally, MgNb2O6 materials exhibited a broad and strong photoluminescence emission near 445 nm with excitation at 270 nm, possibly indicating the presence of radiative defects in the crystalline nanostructure. Furthermore, impedance studies conducted between 40 and 110 MHz demonstrated a decrease in the dielectric constant at higher frequencies, reaching 21.06 at 110 MHz. A low dielectric loss was also observed at 110 MHz. The moderate band gap and strong room-temperature photoluminescence in the visible range make magnesium niobates suitable for possible applications in optical devices. This investigation shows that a dielectric constant near 21 and low dielectric loss can be achieved in the high-frequency range around 110 MHz.

Tweaking the structural, micro–structural, optical and dielectric properties of anatase titanium dioxide via doping of nitrogen ions

The pure nanostructured anatase titanium dioxide (TiO2) and subsequent nitrogen–doped derivatives (TiO2–xNx; where, x = 0.005, 0.01, 0.05) were synthesized by sol–gel auto–combustion technique. XRD analysis confirms the formation of pure anatase phase of TiO2 up to doping of 1 mol% (x = 0.01) of nitrogen having tetragonal structure with space group of I41/amd whereas an additional monoclinic phase of TiO2–B was observed at 5 mol% of nitrogen doping in TiO2. This sample has smallest crystallite size of ∼4.7 ± 0.2 nm corresponding to TiO2–B phase and ∼12.0 ± 0.1 nm corresponding to anatase phase. XRD also reveals that the crystallite size of all other samples having pure anatase phase ranges between ∼8.7 ± 0.1 nm & 13.9 ± 0.1 nm. The crystalline phase revealed from XRD of all samples was further supported by the Raman analysis. The direct optical band gap of pure TiO2 (∼3.4 eV) was reduced non–monotonically after nitrogen doping in the ranges from ∼2.8 eV (TiO1.95N0.05) to ∼2.0 eV (TiO1.99N0.01). FTIR spectra confirm the metal oxide bond formation, surface adsorption of water molecules and presence of residual hydroxyl group in all crystalline samples. HRTEM analysis validates the coexistence of secondary phase of TiO2–B along with anatase phase of TiO2 in studied highest doped sample (TiO1.95N0.05) including its broader particle size distribution as compared to pure TiO2. The electrical studies reveal that the highest values of dielectric constant and ac conductivity can be realized for pure TiO2 and at 1 mol% (x = 0.01) of nitrogen doping, among all the studied nitrogen doped samples.

Sustainable synthesis of iron oxide nanopigments: Enhancing pigment quality through combined air oxidation and cavitation techniques

This study investigates the synthesis and characterization of iron oxide pigments through various methods, including air oxidation, co-precipitation, and hydrodynamic cavitation. The infrared (IR) spectral analysis revealed key functional groups and metal-oxide bonds indicative of goethite, with bands associated with O–H stretching and Fe–O vibrations. The study also explores how different conditions, such as temperature, pH, and reactant ratios, affect the color, yield, and particle size of the pigments produced. Through batch and continuous synthesis processes, it was found that cavitation offers a more controlled particle size distribution compared to other methods. The experiments highlight the influence of parameters like temperature, pH, and NaOH concentration on the final pigment properties, with optimized conditions yielding high-quality pigments. The comparison of synthetic methods demonstrates the trade-offs in terms of reaction complexity, particle size control, and yield, emphasizing the potential of hydrodynamic cavitation for efficient and scalable pigment production. The study concludes by summarizing the versatile reactions of FeSO4 and NaOH in producing various iron oxide and oxyhydroxide materials, which are valuable in industrial and environmental applications.

Exploring a facile preparation method for Co-Ni/MoS2-derived nanohybrid from wheat straw extract and its physicochemical properties.

This study presents a novel approach for the fabrication of a Co,Ni/MoS2-derived nanohybrid material using wheat straw extract. The facile synthesis method involves a sol-gel process, followed by calcination, showcasing the potential of agricultural waste as a sustainable reducing and chelating reagent. The as-prepared nanohybrid has been characterized using different techniques to analyse its physicochemical properties. X-ray diffraction analysis confirmed the successful synthesis of the nanohybrid material, identifying the presence of NiMoO4, CoSO4 and Mo17O47 as its components. Fourier-transform infrared spectroscopy differentiated the functional groups present in the wheat straw biomass and those in the nanohybrid material, highlighting the formation of metal-oxide and sulphide bonds. Scanning electron microscopy revealed a heterogeneous morphology with agglomerated structures and a grain size of around 70 nm in the nanohybrid. Energy-dispersive X-ray spectroscopy analysis shows the composition of elements with weight percentages of (Mo) 9.17%, (S) 6.21%, (Co) 12.48%, (Ni) 12.18% and (O) 50.46% contributing to its composition. Electrochemical analysis performed through cyclic voltammetry showcased the exceptional performance of the nanohybrid material as compared with MoS2, suggesting its possible applications for designing biosensors and related technologies. Thus, the research study presented herein underscores the efficient utilization of natural resources for the development of functional nanomaterials with promising applications in various fields. This study paves a way for manufacturing innovation along with advancement of novel synthesis method for sustainable nanomaterial for future technological developments.

Effect of calcination temperature on structural, optical, and morphological properties of RAlO3 (R = La, Sm) perovskite oxides

RAlO3 (R = La, Sm) have attracted the research community due to their interesting optoelectronic properties and viable applications. The solution combustion method allows for a faster process and lower calcination temperature than the traditional solid-state method and is an economical alternative to wet chemical synthesis for producing RAlO3. This work explores the thermal, structural, morphological, optical, and electrical properties of RAlO3 (R = La, Sm) synthesised by the solution combustion method using urea as fuel. Thermogravimetric analysis—differential thermal analysis (TGA-DTA) showed the crystallization temperatures of lanthanum aluminate (LaAlO3) and samarium aluminate (SmAlO3) at 864 and 887 °C, respectively. The x-ray diffraction (XRD) and Rietveld analysis revealed the structure of LaAlO3 as rhombohedral (R-3c) and SmAlO3 as orthorhombic (Pbnm). The LaAlO3 and SmAlO3 samples calcinated at 800 °C showed crystallite size (D) of 19.26 nm and 19.06 nm, respectively. The field emission scanning electron microscopy (FE-SEM) images show a highly porous and large sheet-like morphology with voids and cracks. High resolution transmission electron microscopy (HR-TEM) images and the selective area electron diffraction (SAED) pattern show crystalline nature and the indexed planes agreed with the XRD results. The LaAlO3 and SmAlO3 samples had specific surface areas of 16.374 and 12.953 m2 g−1, respectively. The TGA-DTA results were affirmed by Fourier transform infrared spectroscopy (FT-IR) results which showed only the presence of metal-oxide bonds for materials annealed at and above 800 °C. These results were further validated by the electron dispersive x-ray spectroscopy (EDX) and the x-ray photoelectron spectroscopy (XPS) showing no additional peaks. The band gap of 5.08 and 4.82 eV were calculated from ultraviolet-visible spectroscopy (UV–vis) for LaAlO3 and SmAlO3, respectively. The results imply that the solution combustion technique using urea as fuel is a viable route for synthesising RAlO3.

Direct Current Pulse Atmospheric Pressure Plasma Jet Treatment on Electrochemically Deposited NiFe/Carbon Paper and Its Potential Application in an Anion-Exchange Membrane Water Electrolyzer.

An atmospheric pressure plasma jet (APPJ) is used to process electrochemically deposited NiFe on carbon paper (NiFe/CP). The reactive oxygen and nitrogen species (RONs) of the APPJ modify the surface properties, chemical bonding types, and oxidation states of the material at the self-sustained temperature of the APPJ. The APPJ treatment further enhances the hydrophilicity and creates a higher disorder level in the carbon material. Moreover, the metal carbide bonds of NiFe/CP formed in the electrochemical deposition (ED) process are converted to metal oxide bonds after APPJ processing. The potential application of APPJ treatment on NiFe/CP in alkaline water electrolysis is demonstrated. With more oxygen-containing species and better hydrophilicity after APPJ treatment, APPJ-treated NiFe/CP is applied as the electrocatalyst for the oxygen evolution reaction (OER) in alkaline water electrolysis. APPJ-treated NiFe/CP is also used in a custom-made anion-exchange membrane water electrolyzer (AEMWE); this should contribute toward realizing the practical large-scale application of AEM for hydrogen production.

Situ synthesis and characterization of polypyrrole/ZnO Nanocomposites for optical and photocatalytic activity

In situ polymerisation process used for manufacturing polypyrrole (PPy) nanoparticle-reinforced various doping concentration of zinc oxide (ZnO NPs) nanocomposites. Fourier transform infrared(FTIR), Scanning electron microscopy(SEM), Photo luminescence (PL) and UV-vis spectroscopy was used to characterise the polymer nanocomposite. The ZnO nanoparticles are distributed throughout PPy matrix as shown in the SEM pictures of the nanocomposites. Distinctive peaks of Pure PPy and metal oxide bond of ZnO are as displayed in the FTIR spectra. Optical property of PPy, ZnO and PPy/ZnO was studied by using PL and UV-DRs spectrophotometer. These outcomes demonstrated that the synthesised PZ30 nanoparticles could potentially use in the treatment of wastewater.

Rare earth Gd3+-substituted Co spinel nanoferrites structural, dielectric and magnetic properties

Gadolinium-doped cobalt ferrite CoGdxFe2-xO4 (CGF) were produced using citrate gel auto-combustion method (x = 0–0.025 at an interval of 0.005). An investigations on the impact of Gd3+ ions on structural, dielectric, and magnetic properties were conducted. The synthesized materials were characterized using the following techniques: X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, ultraviolet visible spectroscopy (UV), impedance (dielectric) analysis, and vibrating sample magnetometer (VSM). The crystalline size ranging from 48 to 13 nm. The Williamson-Hall plots were utilized to examine the impact of crystalline size and lattice strain on the peak broadening of each sample. The X-ray diffraction spectra were used to confirm phase identification and spinel structure. The results of FTIR examinations show that strong metal oxide bonds can be found in the tetrahedral and octahedral sites at wavelengths of 351–376 cm−1 and 567–574 cm−1, respectively. The obtained samples to study optical energy bandgap (Eg), which vary from 2.01 eV to 2.45 eV and show that they are semiconducting materials.The Maxwell-Wagner model and Koop's theory have both been used to study the behaviour of dielectric properties. The dielectric constant at room temperature to 673 K in the frequency range 50 Hz–1 MHz to study the dielectric constant, dielectric loss, AC electrical conductivity, and impedance. The impedance charts show how conductivity was impacted by grain and grain boundary mechanisms. In relation to an applied field of 100 kOe, magnetization was measured at 3 K and 300 K. The blocking temperature (TB), which exhibits super-paramagnetic behaviour, is found to be approximately 359 K according to zero-field cooling ZFC and field cooling. The FC experiments carried out in the temperature range of 3 K–360 K under an applied field of 100 Oe.

Exploring the potential of Withania somnifera-mediated Ag/Mn3O4 nanocomposites as electrode material for high-performance supercapattery device

Background: In this work, a bioengineered symmetric electrode material (anode, cathode) for energy storage devices was successfully demonstrated. Methods: Using Withania somnifera, Ag/Mn3O4 nanocomposite was prepared through sol-gel-assisted green synthesis. Physicochemical properties of Ag/Mn3O4, 431 nm (Ag), 315 nm (Mn3O4) in UV–visible analysis, metal (Ag) and metal oxide (Mn3O4) bonds, crystallinity index with a crystallite size of ∼29 nm from the XRD studies, rod-like morphology (SEM analysis), elemental composition (EDAX analysis), and chemical states (Ag 3d and Mn 2d) were identified through XPS studies. Significant findings: The cyclic voltammetry profiles of Ag/Mn3O4 exhibit the supercapattery behaviour with a specific capacitance of 254 F/g at a scan rate of 5 mVs−1 and a cyclic retention of 92.3 %. The fabricated symmetric supercapattery device (SSD) has an energy density of 18.5 Whkg−1 and a power density of 2084 Wkg−1. The stability of the complex is also studied in theoretically.

Study of Structural and Optical Behaviour of Silver -Copper Bimetallic Nanoparticles

Silver-based nanomaterials have proven interesting and promising material for numerous applications such as biosensor, antimicrobial, anticancer agent, catalyst, food and water treatment, energy storage devices etc.In this study, nanoparticles of Silver and Copper were prepared by chemical reduction method, using hydrazine hydrate and Sodium borohydride as reducing agent. Fine powder of Ag-Cu nanoparticles (NPs)was obtained. The structural analysis of the sample wasdone using Powder XRD, SEM and TEM images and particle size analysis by DLS.The chemical purity and the elemental compositions of synthesized NPs were studied using SEM-EDX. Optical properties of the Ag-Cu NPs were analyzed using UV-DRS spectrum and FTIR spectrum. PXRD reveals that the NPs are highly crystalline in nature.The average crystallite size is30 nm. SEM and TEM images confirm the spherical morphology and the particle size is in nm. The DLS-particle size analyzer shows the size distribution of most of the NPs ranging from 9 nm to 100 nm. The EDX analysis reveals the percentage of elemental composition as 14.71, 9.06 and 76.23 for silver, copper and oxygen respectively. UV-DRS spectrum shows the absorption maximum occur at 371 nm. Due to the synergistic effect of silver and copper, there is blue shift in the absorption maximum. The IR spectrum discloses the metal oxide bond in the synthesized NPs.

Structural, optical and magnetic properties of MgFe2O4 and Ni0.5Zn0.5Fe2O4

Spinel ferrite nanoparticles Nickel zinc ferrite (Ni1-xZnxFe2O4 (x = 0.5)) and magnesium ferrite (MgFe2O4) are synthesized by sol-gel auto-combustion and annealed at 1150 °C and 1200 °C respectively. X-ray diffraction (XRD) confirms the presence of a single-phase cubic spinel structure. Lattice parameters crystallite size and density of ferrites are calculated from the XRD data. Surface morphology of the spinel ferrites is studied using Field Emission Scanning Electron Microscopy (FE-SEM). Optical properties such as bandgap, refractive index, extinction coefficient, dielectric constant, and dielectric loss are calculated using UV–Visible spectroscopy. Two absorption bands for each are identified by Fourier Transform Infrared Spectroscopy (FT-IR) peaks, with the lower frequency (400Hz) corresponding to the metal-oxide bond vibrations at the octahedral site and the higher frequency (600Hz) corresponding to the metal-oxide bond vibrations at the tetrahedral sites of the spinel lattice. Magnetic properties are analysed using Vibrating Sample Magnetometer.

Prediction of nonlayered oxide monolayers as flexible high-κ dielectrics with negative Poisson’s ratios

During the last two decades, two-dimensional (2D) materials have been the focus of condensed matter physics and material science due to their promising fundamental properties and (opto-)electronic applications. However, high-κ 2D dielectrics that can be integrated within 2D devices are often missing. Here, we propose nonlayered oxide monolayers with calculated exfoliation energy as low as 0.39 J/m2 stemming from the ionic feature of the metal oxide bonds. We predict 51 easily or potentially exfoliable oxide monolayers, including metals and insulators/semiconductors, with intriguing physical properties such as ultra-high κ values, negative Poisson’s ratios and large valley spin splitting. Among them, the most promising dielectric, GeO2, exhibits an auxetic effect, a κ value of 99, and forms type-I heterostructures with MoSe2 and HfSe2, with a band offset of ~1 eV. Our study opens the way for designing nonlayered 2D oxides, offering a platform for studying the rich physics in ultra-thin oxides and their potential applications in future information technologies.

Effect of Ce infusion on the structural, dielectric, optical, transport and polarization behavior of Nd-modified triple-layered Aurivillius phase ceramic Bi3NdTi3O12

Herein, the effect of cerium substitution on the structural, dielectric, optical, impedance and leakage current characteristics of Nd modified triple layered Aurivillius phase compound of chemical composition Bi3NdTi3-xCexO12 is investigated. The polycrystalline samples are synthesized via ceramic fabrication technology. Room temperature X-ray analysis confirms their orthorhombic symmetry. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis affirm microstructure and elemental composition of the compounds. The temperature-dependent dielectric study indicates diffused phase transition (DPT) behavior possibly induced by compositional fluctuations and random occupancy of equivalent crystallographic sites. Signature peaks pertaining to metal-oxide bond vibrations are also identified by FTIR study. Impedance spectroscopic study unravels negative temperature coefficient of resistance (NTCR) and non-Debye type relaxation in the samples. UV–Visible spectroscopy reveals a reduction in band-gap from 3.1 eV to 2.83 eV with cerium infusion from x = 0 to x = 0.3. It is due to the introduction of localized mid-gap states thus, suggesting the possibility of photovoltaic applications. Further analysis of electric modulus and impedance characteristics propounds prominent short-range carrier hopping with higher cerium percentage. The room temperature I–V study suggests an increase in the voltage-dependent non-linearity with cerium incorporation. Leakage current analysis reveals a transition from Ohmic to space charge limited conduction (SCLC) type behavior with high electric field. Room temperature polarization study confirms their ferroelectric property. Frequency dependent ac conductivity obeys Jonscher double power law clearly indicating the presence of two dispersive regions dominated by grain and grain boundary effects. Reduced bandgap, enhanced voltage dependent non-linearity, NTCR type property and saturated P-E loops observed in the sample unravel the multifunctional aspects of the fabricated compound.

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.

Annealing Temperature Dependence on Magnetic Properties, Crystalline Structure and Photocatalyst Activity of Coprecipitated Cobalt Ferrite (CoFe2O4) Synthesised from Natural Iron Sand

Cobalt ferrite (CoFe2O4) nanopowder was successfully synthesised by the coprecipitation method. For the entire experiment, natural iron sand from the Bengawan Solo River is used as an iron (Fe) cation source. The effect of the annealing temperature of a coprecipitated CoFe2O4 sample from natural iron sand was investigated. The presence of strong metal oxide bond groups at the tetrahedral and octahedral sites is revealed by fourier transform infrared (FTIR) spectral results, owing to the CoFe2O4 characteristic. Then the X-ray diffraction (XRD) pattern confirmed the formation of a single-phase CoFe2O4 with face centred cubic (FCC) crystal structure closely matched to reference data ICDD221086. The crystalline parameters such as lattice parameter and crystallite size modify with the increase of annealing temperature. The saturation magnetisation (Ms) decreases as the annealing temperature rises. In addition, the coercive fields (Hc) increases as the annealing temperature rises. As a result, the annealing temperature affects the performance of the CoFe2O4 photocatalyst. The photocatalytic performance of the annealing temperature sample at 300°C was found to be the best.

Zircon-Type CaCrO4 Chromite Nanoparticles: Synthesis, Characterization, and Photocatalytic Application for Sunlight-Induced Degradation of Rhodamine B.

The degradation of organic dye pollutants is a critical environmental issue that has garnered significant attention in recent years. To address this problem, we investigated the potential of CaCrO4 chromite (CCO) as a photocatalyst for the degradation of cationic and anionic dye solutions under sunlight irradiation. CaCrO4 was synthesized via a sol-gel auto-combustion route and sintered at 900 °C. The Rietveld refined XRD profile confirmed the zircon-type structure of CaCrO4 crystallized in the tetragonal unit cell with I41/amd space group symmetry. The surface morphology of the sample was investigated by field emission scanning electron microscopy (FESEM), which revealed the polyhedral texture of the grains. Energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) studies were carried out to analyze the elemental composition and chemical states of the ions present in the compound. Fourier transform infrared (FT-IR) spectroscopy analysis revealed the vibrational modes corresponding to the tetrahedral and dodecahedral metal oxide bonds. The optical band gap was approximated to be in the range of 1.928 eV by using the Tauc relation. The CaCrO4 catalyst with different contents (5, 20, 35, and 50 mg) was investigated for its photocatalytic performance for the degradation of RhB dye solution under sunlight irradiation using a UV-Vis spectrometer over the experimental wavelength range of 450-600 nm. The degradation efficacy increased from 70.630 to 93.550% for 5-35 mg and then decreased to 68.720% for 50 mg in 140 min under visible light illumination. The comparative study demonstrates that a higher degradation rate was achieved for cationic than anionic dyes in the order RhB > MB > MO. The highest deterioration (93.80%) was achieved for the RhB dye in 140 min. Equilibrium and kinetic studies showed that the adsorption process followed the Langmuir isotherm and pseudo-second-order models, respectively. The maximum adsorption capacity of 21.125 mg/g was observed for the catalyst concentration of 35 mg. From the cyclic test, it has been observed that the synthesized photocatalyst is structurally and morphologically stable and reusable. The radical trapping experiment demonstrated that superoxide and hydroxyl radicals were the primary species engaged in the photodegradation process. A possible mechanism for the degradation of RhB has been proposed. Hence, we conclude that CaCrO4 can be used as an efficient photocatalyst for the remediation of organic dye pollutants from the environment.

Growth of Nanofibers Zinc Oxide on Porous Silicon Substrates using Electrospinning Method: Effect of Temperatures

Electrospinning successfully grew zinc oxide (ZnO) nanofibers onto porous silicon (PSi). The ZnO sprayed solution was prepared from the mixture of zinc acetate hydrate dissolved in distilled water and polyvinyl alcohol (PVA) precursor with a ratio of 1:3 wt. %. The obtained ZnO fibers sample was subsequently annealed at RT, 100°C, 200°C, and 300°C. ZnO polycrystal with hexagonal wurtzite structure formed on PSi substrates at the orientation of (002), (102), and (110). SEM characterization revealed that the average diameter of fibers decreased with the increased annealing temperature due to the decomposition of the PVA and acetate groups. The ATR-FTIR spectral showed the presence of a metal oxide bond group owing to ZnO characteristics on the PSi surface.

Synthesis, characterization, and nonlinear optical properties of copper (II) ligand Schiff base complexes derived from 3-Nitrobenzohydrazide and benzyl

A new series of Cu (II) complexes were prepared using Schiff base ligand of N–N′-(1,2-diphenyl ethane-1,2-diylidene)bis(3-Nitrobenzohydrazide). The prepared ligand and Cu (II) complex were characterized using various physicochemical investigations such as X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), and Energy dispersive X-ray analysis (EDX), Fourier Transform Infrared (FT-IR), {}^{13}C Nuclear Magnetic Resonance (NMR), {}^{1}H NMR, Diffuse Reflectance Spectroscopy (DRS), Vibrating Sample Magnetometer (VSM), and Z-Scan technique (Nonlinear optical (NLO) properties). In addition, the prepared samples have been examined for their NLO characteristics with the help of the Density Functional Theory calculations which proved that the Cu (II) Complex is more polarized than Ligand. According to XRD and FESEM results, the nanocrystalline nature of the samples is confirmed. The metal-oxide bond assigned in the functional studies by FTIR. Magnetic studies demonstrate weak ferromagnetic and paramagnetic nature for Cu (II) complex and diamagnetic nature for the ligand, respectively. DRS spectrum exhibited higher reflectance for Cu (II) than the ligand. The band gap energies of the synthesized samples were estimated by employing the Tauc relation and Kubelka–Munk theory on reflectance data and found to be 2.89 eV and 2.67 eV for Cu (II) complex and ligand, respectively. Extinction coefficient and refractive index values were calculated using the Kramers–Kronig method. The z-scan technique was applied to estimate the NLO properties by a 532 nm Nd:YAG laser.

Optimization of the structural, optical, and magnetic properties of sol-gel derived La3+ substituted nanostructured barium hexaferrites

The M-type barium hexaferrites have been considered an impeding material for their use as microwave absorbers and storage devices. In present investigation, the La3+ substituted M-type BaFe12−xLaxO19, (where x = 0, 0.2, 0.4, 0.6, 0.8 and 1) was prepared via a facile sol-gel process at 850 °C for 3 h. XRD confirmed the hexagonal crystal structure of La3+ substituted BaFe12O19 belonging to P63/mmc space group with the crystallite size in the range of 23.08–39.59 nm, which decreased with the increase in La3+ content. The Rietveld refinements displayed better goodness of fit (χ 2), which was observed between 1.20–1.90 for proper peak fitting. The W-H plot indicated the decrease in lattice strain (0.21 × 10–3–2.14 × 10−3) with the increase in La3+ contents. The SEM imaging revealed the agglomerations and estimated the average grain size in the range of 0.42–3.69 μm. FTIR spectroscopy confirmed the bands in the range of 432–622 cm−1, which represents stretching and bending vibrations of metal oxide bonds. The tetrahedral site exhibited a higher force constant and lower bond length than the octahedral site in M-type barium hexaferrite. The photoluminescence spectroscopy demonstrated that a prominent peak of La3+ substituted BaFe12O19 near 481 nm, which falls under the visible range with strong blue emission and indicates the radiative defects present in the crystal. At room temperature, the magnetic measurements indicate that the coercivity (Hc) increased, but the saturation magnetization (Ms) and the retentivity (Mr) decreased with the increase in La3+ substitutions. The anisotropy constant (K) and Bohr magnetron number (nB) were also evaluated between 0.932 × 106−1.109 × 106 erg cm−3 and 10.28–11.68 μB, respectively. Hence, the unique photoluminescence and magnetic properties may be responsible for its application in the electronic industry, telecommunication, microwave engineering and storage devices etc.

Green synthesised zinc oxide nanoparticles reveal potent in vivo and in vitro antibacterial efficacy against Proteus mirabilis isolates

Currently, the spread of antimicrobial resistance dissemination is expanding at an accelerated rate. Therefore, numerous researchers haveinvestigatedalternative treatments in an effort to combat this significant issue. This study evaluated the antibacterial properties of zinc-oxide nanoparticles (ZnO NPs) synthesised by Cycas circinalis against Proteus mirabilis clinical isolates. HPLC was utilised for the identification and quantification of C. circinalis metabolites. The green synthesis of ZnO NPs has been confirmed using UV–VIS spectrophotometry. The Fourier transform infrared spectrum of metal oxide bonds has been compared to the free C. circinalis extract spectrum. The crystalline structure and elemental composition were investigated using X-ray diffraction and Energy-dispersive X-ray techniques. The morphology of nanoparticles was assessed by scanning and transmission electron microscopies, which revealed an average particle size of 26.83 ± 5.87 nm with spherical outlines. The dynamic light scattering technique confirms the optimum stability of ZnO NPs with a zeta potential value equal to 26.4 ± 0.49 mV. Using agar well diffusion and broth microdilution methods, we elucidated the antibacterial activity of ZnO NPs in vitro. MIC values for ZnO NPs ranged from 32 to 128 µg/mL. In 50% of the tested isolates, the membrane integrity was compromised by ZnO nanoparticles. In addition, we assessed the in vivo antibacterial capacity of ZnO NPs by a systemic infection induction using P. mirabilis bacteria in mice. The bacterial count in the kidney tissues was determined, and a significant decrease in CFU/g tissues was observed. The survival rate was evaluated, and the ZnO NPs treated group had higher survival rates. The histopathological studies demonstrated that kidney tissues treated with ZnO NPs had normal structures and architecture. Moreover, the immunohistochemical examinations and ELISA revealed that ZnO NPs substantially decreased the proinflammatory mediators NF-kβ, COX-2, TNF-α, IL-6, and IL-1β in kidney tissues. In conclusion, the results of this study suggest that ZnO NPs are effective against bacterial infections caused by P. mirabilis.