Sol-gel Method Research Articles

Influence of rapid heat treatment on the photocatalytic activity and stability of calcium titanates against a broad range of pollutants

Calcium titanate (CTO) photocatalysts were synthesized using a sol–gel method by adopting a cost-efficient, rapid calcination technique. The CTOs were characterized by X-ray diffractometry, X-ray photoelectron spectroscopy, infrared spectroscopy, nitrogen adsorption, porosimetry measurements, scanning/transmission electron microscopy, and diffuse reflectance spectroscopy. Their photocatalytic activity was assessed through the photocatalytic degradation of phenol, oxalic acid, and chlorophenol under UV light exposure, using a commercial CTO as a reference. The stability of the samples was evaluated using compounds with –OH, –COOH, and –Cl functional groups. Characterization results showed that CTO composites containing anatase, rutile, and brookite titania were obtained. Increasing the calcination temperature led to various crystalline compositions, higher crystallinity, larger primary crystallite sizes, and smaller specific surface areas. The photocatalytic activity of all CTO/TiO2 composites was superior compared to the commercial CTO we used as a reference. The high photocatalytic activity of the best-performing composites was attributed to their higher specific surface areas and the synergistic effect between the crystal phases. A cost comparison was also made between our unique calcination technique and conventional calcination, and it was found that our method is approximately 35% more cost-effective, while retaining the photocatalytic activity.

Fabrication of single-ion conductive quasi-solid-state electrolyte membrane for high-performance lithium-ion batteries

The aim of this work is to develop new quasi-solid-state electrolyte materials for lithium-ion batteries (LIBs) to improve their safety and comprehensive electrochemical performance. Herein, helical mesoporous silica nanofibers were synthesized by a sol–gel method. After grafting lithium salt onto their surfaces, a single-ion conductor (SL) was obtained. Then, using poly(vinylidene fluoride-co-hexafluoropropylene) as the polymer matrix, SL as the filler, a porous composite film was prepared by solution casting method. After soaking organic electrolyte with low concentration Li salt till saturation, one quasi-solid-state electrolyte membrane (PSLE) was achieved. It showed high electrolyte adsorption rate of 660 % and good thermal stability. A high lithium-ion transfer number of 0.85 indicated typical single-ion conductivity. Moreover, a high electrochemical stability window of up to 5.5 V and an ionic conductivity of 2.5 × 10−3 S·cm−1 at 25 °C were gained. The assembled LFP|PSLE|Li battery exhibited excellent rate performance and cycle stability, indicating that the PSLE has great application prospect in solid-state LIBs.

A-site doped LaFeO3 perovskite for highly active O3 catalytic decomposition

Nowadays, the treatment of ozone has become critically important due to the health risks caused by even minimal amount of ozone in the ambient air. In this work, LaFeO3 doped with Mg, Ca, Sr and Ce on A-site are synthesized by sol-gel method and adopted as a highly active ozone decomposition catalyst. The results show that the Ce doped LaFeO3 exhibits the highest catalytic activity with the optimal doping concentration marked as La0.5Ce0.5FeO3. It reaches high conversion efficiency of 97% and 90% to 1000 ppm ozone at high weight hourly space velocity of 720,000 and 1,440,000mLg-1 h-1, which is one of the highest in the literature. The distortion of [FeO6] octahedra reached the maximum when the doping amount of Ce was 0.5 as revealed by X-ray diffraction and Rietveld fitting. The high ozone catalytic activity could be assigned to the easy electron loss from eg orbit caused by high crystal field splitting energy, abundant oxygen vacancies resulting from the biggest distortion of [FeO6] octahedra and quick transfer between Fe2+ and Fe3+.

Innovative approach for trace level detection of mefenamic acid by ferrite nanocomposite-based electrochemical sensor

In the present work, the rapid and highly efficient catalyst has been designed for the electrochemical sensing of the non-steroidal drug Mefenamic acid (MFA) for quality control and clinical assessment. Ferrite nanocomposite (SFBF-NC) has been synthesized by sol-gel method from the precursor sodium ferrite and barium ferrite and applied for the electrochemical sensing of MFA. The SFBF-NC was examined by various analytical methods to confirm its coral-like shape with a highly rough and porous structure, cubic/spinal phase crystallinity, and average crystalline size < 60 nm with good stable electronic properties. Due to the large electroactive surface area, fast electron transfer rate, and potent electrocatalytic activity of SFBF-NC, the fabricated SFBF-NC/GCE showed good sensitivity for the quantitative determination of MFA. The proposed sensor showed the limit of detection (LOD) of 2.12 nM with a linear range of 0.01–450 μM for MFA detection. Additionally, the proposed sensor demonstrated excellent catalytic activity, stability, repeatability, and selectivity for MFA sensing and was utilized for the routine analysis of MFA in biological and pharmaceutical samples.

The synergistic enhancement of photocatalytic activity by Fe3O4–TiO2 nanosheets for rhodamine B degradation

As an advanced oxidation material, Fe3O4-TiO2 nanocomposites have been widely used in wastewater treatment. However, conventional Fe3O4 nanoparticles suffer from drawbacks such as carrier recombination and aggregation, which seriously affect the catalytic activity. In this study, Fe3O4-TiO2 nanosheets with different TiO2 loading rates were synthesized by sol-gel method and solvothermal method. The unique two-dimensional nanostructure of Fe3O4 nanosheets facilitated the deposition of TiO2 nanoparticles, resulting in Fe3O4-TiO2 nanosheets with a high BET specific surface area of 121.67 m2·g−1. Under optimal experimental conditions, the degradation rate of RhB dye in the photocatalytic synergistic Fenton-like system constructed with Fe3O4-TiO2 nanosheets reached 98.12 % within 120 min, significantly surpassing that of single photocatalysis and Fenton-like systems. It was attributed to the unique surface structure of Fe3O4 nanosheets, which provided a larger contact area for TiO2 nanoparticles. It facilitated the effective reduction of Fe3+ to Fe2+ by photogenerated electrons in TiO2, inhibited the recombination of photogenerated electron-hole pairs, and consequently enhanced the degradation rate of RhB dye. Furthermore, Fe3O4-TiO2 magnetic nanosheets exhibited excellent reusability and stability, with the recovery rate and degradation rate of RhB dye remaining above 90 % even after five cycles. More importantly, the catalytic mechanism of Fe3O4-TiO2 nanosheets was elucidated, and •OH identified as the primary reactive species responsible for degrading RhB dye. This work provides a novel research direction for designing and preparing advanced catalytic degradation materials, offering a practical solution to the challenging issue of wastewater treatment.

Resistive switching behavior and thermal stability in the flexible BEFO/ZnO/LSMO heterostructure for flexible/wearable electronics

With the advent of the internet era, wearable electronic devices and flexible electronic technology are rapidly emerging, and new resistive random access memory (RRAM) based on flexible substrates have thus gained extensive attention. Here, the flexible Bi0.95Er0.05FeO3/ZnO/La0.66Sr0.34MnO3 (BEFO/ZnO/LSMO) heterostructure is prepared on Mica substrate using the sol-gel method. The high resistance state (HRS) to low resistance state (LRS) ratio consistently surpasses 102 under the flat and the 15 mm bending radius state. There is no significant change in the resistive switching (RS) behavior after 30 I-V curve cycles and 103 write/erase operations on the BEFO/ZnO/LSMO heterostructure, which reflects excellent stability. In addition, the device still works properly at 175°C for dynamic conversion between HRS and LRS. The observed RS behavior in the BEFO/ZnO/LSMO heterostructure is attributed to ion migration and alterations in the potential barrier height at the interfaces. These results suggest that the BEFO/ZnO/LSMO heterostructure based on a flexible Mica substrate plays a crucial role in the development of next-generation portable and flexible electronic systems due to its excellent flexibility and thermal stability.

Sol–gel derived red fluorescent nanocomposites of copper nanoclusters conjugated silica for visualizing latent fingerprints

Phosphors with red emission have attracted increasing interests due to their high contrast and low interferences of fluorescence background which play a vital role in visualizing latent fingerprints (LFPs) in forensic science. In this work, red-emissive fluorescent nanocomposites of copper nanoclusters conjugated silica (CuNCs/silica) are prepared simply by sol-gel method in one pot for visualizing the LFPs through powder-dusting method. The CuNCs/silica exhibits the red fluorescence with an emission wavelength of 628 nm under the excitation of 292 nm and can have sufficient affinity with the LFPs ridges. The CuNCs/silica with the photoluminescence properties can precisely visualize and capture the clear patterns and the well-defined details of the LFPs ridges on the non-porous and semi-porous surfaces of different substrates (including copper foil, compact disc, tiles, stainless steel, aluminum foil, glass slide, Hong Kong currency, colored plastic packing, colored paper and leather) even with fluorescent background. The ridge details of the aged LFPs can also be clearly identified. These suggest the great potential of the CuNCs/silica as phosphors for visualizing the LFPs in criminal investigations.

The magnificent manifestation of Nd0.7Sr0.3MnO3 ceramics: A comprehensive exploration of different wet chemical routes via sol-gel and thermal treatment methods

The mixed-valence manganite has sparked immense interest owing to its intriguing colossal magnetoresistance (CMR) effect. However, a research gap exists in the current literature regarding Nd-based manganites with intermediate bandwidth. This paper addresses this gap by investigating Nd0.7Sr0.3MnO3 (NSMO) ceramics prepared through two different synthesis approaches: the newly developed thermal treatment method (TT) and the well-established sol-gel method (SG). The XRD analysis revealed a single high-purity NSMO phase with insignificant alteration in Mn-O bond length and Mn-O-Mn bond angle for both samples. Nevertheless, SG exhibited larger particle size (209.3nm) and better crystallinity in comparison to TT (178.6nm). These factors significantly affect the magnetic transition width while preserving the Curie temperature, TC ≈ 246K. Regarding electrical behaviour, TT showed a robust suppression of the metal-insulator transition temperature, TMI from 224K (SG) to 182K. This difference can be attributed to the existence of magnetic disordered layer at the grain boundaries. Consequently, this resulted in an increased scattering process and elevated resistivity from 8 Ω (SG) to 22 Ω (TT). Various theoretical models were employed to elucidate the transport mechanism at different temperature ranges. Interestingly, both samples displayed distinct magneto-transport behaviour despite negligible differences in their structural parameters. The occurrence of magnetoresistance peak in SG suggests a pronounced intrinsic CMR effect, while its absence in TT implies a dominant influence of extrinsic CMR. These findings highlight that the physical properties of the manganite are not only governed by their intragrain properties (TC) but are also influenced by intergrain contributions (TMI) when various synthesis routes were utilised.

Impact of electron-beam and gamma-ray on the compressive strength, surface features and phase composition of β-Ni(OH)2-impregnating-geopolymer pastes

In the sol-gel method, nano-materials are obtained by the calcination of the produced hydroxide, which represents several drawbacks, such as high toxicity, high cost and high energy consumption. Therefore, for the first time, β-Ni(OH)2 was used instead of nano-NiO to develop green geopolymeric composites with high-dose radiation tolerance. The mix-design was formulated using slag and fly ash (1:1) activated with 5wt.% NaOH and modified with 0.5, 1 and 2wt.% β-Ni(OH)2. The fresh properties were investigated. It was found that increasing the β-Ni(OH)2 dose reduces workability (mini-slump test) with a slight increase in density. A compressive strength test was performed for all specimens before (cured for 28-days) and after exposure to different radiation doses (100, 200 and 300 KGy). Electron-beam and gamma-ray were used as various sources of radiation. The results demonstrated that incorporating β-Ni(OH)2 in the non-irradiated and irradiated composites enhanced their performance at all additional levels. The irradiation process by electron-beam and gamma-ray positively impacts the compressive strength at all radiation doses, especially at 200 KGy. The highest compressive strength was achieved by the specimen containing 0.5wt.% β-Ni(OH)2 (67.3MPa at 28-days, 88MPa at 200KGy/electron-beam and 76.5MPa at 200KGy/gamma-ray). The XRD, TGA/DTG and SEM analysis techniques proved that the synergistic impact of β-Ni(OH)2 (high reactivity and filling/catalytic impact) and irradiation process (activation unreacted precursors) motivate the formation of new binding phases such as NiAl2O4, CaNiSi2O6 and analcime as well as ordering zeolitic phases in cross-linked structure, causing improvement in the performance.

Preparation, electronic structure and thermal properties of Zn-doped LaMgAl11O19 materials

LaMgAl11O19 (LMA) with magnetoplumbite structure is a promising thermal barrier material due to its excellent thermal properties. In this work, Zn-doped LMA materials were studied in order to improve the thermal performance, and LaZnxMg1-xAl11O19 (x = 0, 0.1, 0.3, 0.5, 0.7, 1.0) were prepared by sol-gel method. The as-synthesized powder materials possess pure LMA phase and show the morphology of hexagonal plates. X-ray photoelectron spectroscopy result shows that there are AlO4 tetrahedra and AlO6 octahedra units in the target materials, and Zn2+ ions replace Mg2+ ions to occupy the tetrahedral position of magnetoplumbite structure. The composition LaZn0.3Mg0.7Al11O19 material exhibits the lowest thermal conductivity of 0.38 W/(m·K) at 1000oC while maintaining a high coefficient of thermal expansion (10.86×10-6 K-1). Therefore, the thermal properties of LMA materials can be improved by adding an appropriate amount of Zn ions.

A comprehensive study on the phase composition, mechanical properties and stability of Li4SiO4-Li2ZrO3 biphasic ceramics

Lithium orthosilicate (Li4SiO4) is regarded as a candidate for tritium breeding in fusion reactors. In this study, the Li4SiO4-Li2ZrO3 biphasic was developed to improve the sinterability, density, and mechanical properties of Li4SiO4. The Li4SiO4-xLi2ZrO3 (x = 0.5, 1) composite powders were prepared using solid-state reaction via in-situ method. Li6Zr2O7 existed in the ceramic powders at low calcination temperatures. When the calcination temperature was increased to 900 °C, Li6Zr2O7 was transformed into Li2ZrO3 due to the decomposition of Li6Zr2O7 at high temperatures. The TEM observation confirmed that the powders consisted of Li4SiO4 and Li2ZrO3. The Li4SiO4 and Li4SiO4-xLi2ZrO3 (x = 0.5, 1) pebbles were fabricated by the sol-gel method. The measurement results showed that the pebbles had a narrow size distribution and fine sphericity. The density of Li4SiO4-Li2ZrO3 pebbles reached 96.01 % of the theoretical density when it was sintered at 1000 °C for 4 h. Compared with the Li4SiO4, the grain size of ceramic pebbles was significantly reduced. Owing to decreased grain size, 139.0 N crush load for the pebbles and 92.4 MPa bending strength for the sintered body were achieved. Besides, the ceramics with the Li4SiO4 to Li2ZrO3 ratio of 2: 1 exhibited preferable mechanical properties. Further, to investigate the chemical stability of biphasic ceramics, the structure and mechanical properties were examined under high temperatures and continuous inert gas purging, simulating the working condition of fusion reactors. It was shown that there was almost no change in phase composition and grain size after purging for 60 h at 650 °C. For the mechanical properties, the crush load was decreased initially due to the cracking in the surface region of the ceramic and then increased because the cracking was recovered.

Synthesis of La1-xSrxCoO3-δ and its catalytic oxidation of NO and its reaction path

The oxidation rate of NO to NO2 is a critical parameter in the removal of NOx within selective catalytic reduction (SCR) systems. LaCoO3-δ is a kind of potential catalyst to enhance the oxidation of NO to NO2, it may offers an economic and stable alternative to noble metal catalysts, particularly at elevated temperatures. This study aimed to enhance the catalytic efficiency of LaCoO3-δ through strontium (Sr) doping. La1-xSrxCoO3-δ (with varying x values of 0.1, 0.2, 0.3, 0.4) was synthesized using a sol-gel method. La1-xSrxCoO3-δ exhibited superior NO oxidation catalytic activity compared to LaCoO3-δ, with the most notable enhancement observed at x = 0.3 (84% conversion). This improvement can be attributed to the substitution of La3+ with Sr2+, which induces lattice distortion and charge imbalance, thereby creating more oxygen vacancies that enhance the catalytic oxidation capability of La1-xSrxCoO3-δ. However, it's important to note that an excessive amount of Sr can result in the formation of SrCO3 deposits on the surface of La1-xSrxCoO3-δ, thereby diminishing its catalytic oxidation performance. The catalytic oxidation reaction behavior adhered most closely to the O2-adsorbed E-R model, the surface defects in La1-xSrxCoO3-δ playing a pivotal role in the catalytic reaction.

Fabrication of carboxymethyl cellulose/graphene oxide/ZnO composite hydrogel for efficient removal of fuchsin dye from aqueous media

Hydrogels are hydrophilic, insoluble, and highly porous 3D networks capable of absorbing large amounts of water. This study aimed to develop a carboxymethyl cellulose/graphene oxide (CMC/GO) hydrogel, cross-linked with citric acid and modified with zinc oxide (ZnO) nanoparticles (CMC/GO/ZnO), synthesized via the sol-gel method. The formulated composite hydrogel samples were characterized by Fourier transmittance infrared spectroscopy (FTIR), scanning electron microscopy (SEM) analysis, X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermo-gravimetric analysis (TGA). The hydrogels were tested for the adsorption of basic fuchsin (BF) dye from the aqueous medium under various conditions, such as adsorbent dosage, contact time, pH, and temperature, using batch adsorption. The adsorption data best fit the Langmuir and Temkin models, with maximum adsorption capacity (qmax) of 172.41 mg/g for CMC/GO and 303.03 mg/g for CMC/GO/ZnO. Optimal adsorption occurred at pH = 6 and within 30 min. The process followed a pseudo-second-order kinetic model, and thermodynamic results indicated that the adsorption process is physical, endothermic and spontaneous. The COOH groups in the hydrogels enhanced affinity for cationic dyes through hydrogen bonding and electrostatic interactions. Thus, CMC/GO and CMC/GO/ZnO hydrogels are efficient and promising adsorbents for environmental remediation.

Design of ZnS nanospheres antireflective structure for mid and far infrared applications

Developing high-performance mid and far infrared antireflection films is a significant requirement in the field of infrared optics. This study successfully prepared AR films composed of ZnS nanospheres for mid and far infrared bands using a combination of hydrothermal and sol-gel methods. Initially, ZnS nanospheres with uniform size and good monodispersity were synthesized via the hydrothermal method and subsequently coated on CdSe substrate through dip coating. The refractive index of the ZnS film is adjusted between 1.36 and 1.52. A significant AR effect was observed in ZnS nanospheres film on CdSe substrate at 3–5 μm and 8–14 μm, and the reflectance is approximately 3 % which is about 25 % lower than that of the uncoated sample. Upon coating with a TiO2 protective layer, the reflectivity further decreased to about 0.6 % and the film demonstrated excellent weather resistance and mechanical properties. This work provides a novel approach for the preparation and regulation of mid and far infrared AR film, significantly contributing to the development of optical film.

Tunable Magnetic and Dielectric Properties of BaMg0.4Al0.4Fe11.2O19 and SiO2 Composites for High-Frequency Applications

This study focuses on the synthesis and characterization of Mg and Al co-doped M-type Barium hexaferrite (BaMg0.4Al0.4Fe11.2O19) powder via the sol-gel method. Structural analysis using X-ray diffraction (XRD) and Fourier transformation infrared spectroscopy (FTIR) confirmed the single-phase structure of the synthesized powder. Morphological properties were examined through field emission scanning electron microscopy (FESEM), revealing hexagonal particle morphology with an average size of approximately 60 nm for BaMg0.4Al0.4Fe11.2O19. To fabricate composites, commercially purchased SiO2 was used to prepare the composites of (1–x) BaMg0.4Al0.4Fe11.2O19+ (x) SiO2 {where x = 0.0, 0.1, 0.3, 0.5 and 0.7). The composites were prepared using the mixing method followed by microwave sintered at 1000 °C/90 min. FESEM and energy-dispersive X-ray spectroscopy (EDS) were employed to analyze the morphology and elemental composition of the composites. The composites ‘ frequency-dependent complex permittivity was measured over 300 kHz to 3 GHz. Magnetic hysteresis (M-H) loops were used to analyze the magnetic properties of composite samples. A reduction in magnetic saturation was observed with increasing SiO2 concentration, while there was a slight increase in coercivity for the composite samples compared to pure hexaferrite. Coercivity remained relatively unchanged with varying SiO2 concentrations in the composites. A possible relation between the magnetic and dielectric properties and the microstructure of the sintered composites with the composition variation was investigated.

Enhanced detection of 4-nitrophenol in drinking water: ECL sensor utilizing velvet-like graphitic carbon nitride and molecular imprinting

In this work, a molecularly imprinted electrochemiluminescence (ECL) sensor was developed for selective detection of 4-nitrophenol (4-NP) in drinking water for the first time. By synthesizing velvet-like graphitic carbon nitride (V-g-C3N4) via one-step thermal polycondensation and integrating it with a molecularly imprinted polymer (MIP), the ECL sensor was fabricated. The MIP-modified V-g-C3N4 composites (MIP/V-g-C3N4) were synthesized using a sol-gel method with 4-NP as the template molecule. Under optimal conditions, the ECL sensor exhibited a wide detection range (5 × 10−10-1 × 10−5 mol/L) and a low detection limit (1.8 × 10−10 mol/L). In testing with actual drinking water samples, it displayed high accuracy (recoveries for intraday and inter-day: 93.50–106.2% and 97.00–107.3%, separately) and precision (RSDs for intraday and inter-day: 1.54–4.59% and 1.53–4.28%, respectively). The developed MIP-based ECL sensor demonstrated excellent selectivity, stability, and reproducibility, offering a promising and reliable approach for highly sensitive and selective determination of 4-NP in drinking water.

Synergistic photocatalysis and superior supercapacitor performance of cerium-enriched monodispersed nanoarchitectures: Dual excellence

Researchers are being focused on designing sustainable and renewable energy storage systems, especially electronically tuned energy storage devices, due to increased electricity demand and fossil fuel depletion. Batteries and supercapacitors have substantially improved energy storage in recent years. In the course of developing nanomaterials with sustainable dual functionality, this study reviews the synthetic and dual applications of cerium-enriched copper oxide monodispersed nanomaterials, especially their synergic photocatalysis, which is much better than their superior supercapacitor storage. The sol-gel method was used for the preparation of nanoarchitectures, in which the crystalline structure and morphology were studied using X-Ray diffraction spectroscopy (XRD) and Scanning electron microscope (SEM) techniques. An important fact is that the nanoarchitectures with 10 % cerium showed their crystallite size, which was reported to be 17.30 nm, implying accuracy in the synthesis. The results of SEM indicate single-phase particles with slight agglomeration. The corresponding 10 % CeO2@CuO nanostructures were then comprehensively evaluated for both photocatalytic activities and energy storage purposes. In relation to photocatalysis, nanoarchitectures proved to be efficient for Rhodamine B (RhB) dye with 92 % degradation after 200 min of the reaction time. Moreover, the synthesized nanoparticles demonstrated excellent supercapacitor performance. The tailor-synthesized nanoarchitectures had a specific capacitance of 875 F/g and energy density achieved 78 Wh/g, which clearly shows the prospect for such materials used in high-energy storage devices. The10 % CeO2@CuO nanoarchitecture retained 88 % of capacitance for 2000 cycles, which made it possible to demonstrate the good robustness and durability of the materials for long-term utilization in energy storage. These findings contribute to the field of nanoscience and nanotechnology, offering a hopeful channel for the future development of advanced materials that have dual functionality.

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 °C for 5 h. 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.

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.

Photocatalytic oxidative desulfurization of a model fuel using S-doped TiO2/BiVO4 composites: A combination of experimental and theoretical study

In this work, a simultaneous photocatalytic extraction-oxidation system for desulfurization of a model fuel has been investigated. To do this, S-doped TiO2 and S-doped TiO2/BiVO4 photocatalysts were synthesized via sol-gel and hydrothermal methods. Different analyses such as FT-IR, Raman, DRS, XRD, FE-SEM, TEM, BET, EDS, and XPS were used to characterize catalysts. According to the results, the S-doped TiO2/BiVO4 catalyst showed the highest photocatalytic activity for the removal of dibenzothiophene from the model fuel. The reaction was investigated under different conditions such as the catalyst amount, temperature, time, oxidizing value, extracting solvent, and the fuel type. Under optimal conditions, 89.3% removal of dibenzothiophene was obtained. The catalyst can be recovered up to 3 times without significant reduction in catalytic activity. To evaluate the effect of the TiO2/BiVO4 heterojunction on its photocatalytic activity, DFT calculations were conducted. The obtained results confirmed the greater efficiency of the synthesized composite.