Journal of Sol-Gel Science and Technology最新文献

Researchers are working on innovative strategies to overcome the threats of environmental deterioration and energy crisis. In this regards, rare earth metal-based nanocomposites are under concern due to their excellent electrochemical performance. In this study, Sm₂O₃/NiFe₂O₄ based nanocomposite was prepared via sol-gel approach for the assessment of Supercapacitor and water splitting applications. The prepared nanocomposites were characterized with distinct techniques, like Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDX). The XRD confirmed the formation of Sm₂O₃/NiFe₂O₄ crystal system. However, SEM depicted a hybrid integrated uniform structure with improved surface morphology while transmission electron microscope demonstrated well dispersed hybrid morphology. The Sm₂O₃/NiFe₂O₄ nanocomposite demonstrated an specific capacitance and energy density of 1975.4 F/g and 68.5 Wh/kg, respectively at 5 mV/s. Furthermore, hydrogen evolution reaction of prepared nanocomposite material showed lower over potential value 209 mV at 10 mA cm^–2. Similarly, the Sm₂O₃/NiFe₂O₄ depicted the Tafel slope of 107 mV/decade better than pure electrode material.

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In the current study, the magnetic, dielectric, and structural properties of Er³⁺ and Er³⁺/Yb³⁺ co-doped Zn_0.88Fe_0.05Co_0.06Ni_0.01O nanocomposites were thoroughly investigated to identify their potential applications. The sol-gel method was employed to synthesize the nanocomposites, while their structural characteristics were analyzed using transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Changes in crystallinity, lattice parameters, and crystallite size (D) resulted from the successful incorporation of Fe, Co, Ni, Er, and Yb ions into the ZnO nanostructure. According to the TEM images, the nanoparticles (NPs) exhibit both spherical and hexagonal shapes, with sizes ranging from 15 to 25 nm, which aligns well with the XRD results. The dielectric properties were investigated using an impedance analyzer, which revealed a decreased dielectric constant (ε‘) and dielectric loss (tan δ) over a wide frequency range. Magnetic measurements conducted using a vibrating sample magnetometer (VSM) revealed ferromagnetic behavior resulting from dopant incorporation, indicating the material’s suitability for spintronic and electromagnetic interference (EMI) shielding applications. The observed structural and functional properties were closely linked to dopant concentrations and microstructural development, providing valuable insight into the versatility of ZnO-based nanocomposites. These results demonstrate the potential of Er³⁺ and Er³⁺/Yb³⁺ co-doped Zn_0.88Fe_0.05Co_0.06Ni_0.01O nanocomposites for advanced magnetic and electronic applications.

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Er³⁺/Yb³⁺ co-doping enhances magnetism and electrical conductivity of ZnO nanostructure without altering its wurtzite crystal structure.

The sol–gel method was used in this work to create Cu and Ga-doped ZnO nanoparticles. The single-phase hexagonal wurtzite ZnO structure is shown by the doped ZnO nanoparticles’ XRD spectra. The addition of Cu and Ga has no effect on the wurtzite structure. The TEM images show that the formation of Cu and Ga-doped ZnO nanoparticles occurs in a range of sizes and has a spherical form. The sol–gel method yielded Cu and Ga-doped ZnO nanoparticles with average particle sizes of about 30–45 nm. For ZnO, ZnO_Cu, ZnO_Ga, and ZnO_Cu/Ga nanoparticles, the calculated bandgap values are 3.34 eV, 3.29 eV, 3.06 eV, and 3.11 eV, respectively. The Cu and Ga-doped ZnO nanoparticles’ luminescence spectra reveal emission that is concentrated in the 400–450 nm range. Magnetic measurements of Cu and Ga-doped ZnO nanoparticles show a diamagnetic behavior in the high field range. All of the nanoparticles have improved electrical conductivity, which makes them suitable for optoelectronic uses.

The composite of mullite/ZnₓCo₁₋_xFe₂O₄ ferrite, where (x = 0.15, 0.3, 0.45), demonstrates a high efficiency in removing malachite green (MG) dye from aqueous solutions. The experimental studies revealed that the prepared composite adsorbent achieves >90% malachite green removal efficiency under pH 7, composite dosage (0.05 g/L), and contact time 0–80 min. (at 0, 3, 6, 15, 25, 40, 60, 80 min intervals). Characterization via XRD and FTIR confirms the presence of mullite and ferrite in composite samples. The adsorption method was used to study the removal of malachite green dye using mullite and the prepared mullite-ferrite composites at a 50% addition ratio. The results showed an increase in the removal efficiency when ferrite was added to mullite, and this increase was improved by increasing the zinc content in cobalt ferrite. The equilibrium adsorption capacity for mullite and the composites were extracted by studying the MG dye adsorption at different times. A quasi-first- and second-order kinetic model was used to calculate the equilibrium adsorption capacity. Adsorption kinetics follow the pseudo-second-order model, indicating chemisorption-dominated mechanisms. The quasi-second-order kinetic model’s results were in good agreement with the experimental, which indicated that the cobalt zinc ferrite increased in tandem with the adsorption efficiency.

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African swine fever virus (ASFV) is a highly contagious and lethal pathogen that poses a serious threat to pig production and leads to significant economic losses. This study aimed to develop nanosystems based on iron oxide (Fe₃O₄) using different extracts (in different solvents) of Stixis scandens leaves and to evaluate their antiviral activity against ASFV. The synthesized nanosystems were characterized using various techniques, including Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV–Vis), field emission scanning electron microscopy (FESEM), dynamic light scattering (DLS), X-ray diffraction (XRD), vibrating sample magnetometry (VSM), and thermogravimetric analysis (TGA). The total polyphenol (TP) and total alkaloid (TA) content of the extracts was quantified, as well as the corresponding loading and release profiles from the nanosystems. The Fe₃O₄ nanoparticles exhibited a uniform size distribution (10–15 nm), high colloidal stability (zeta potential ranging from –106.0 mV to –65.2 mV), superparamagnetic behavior, and efficient heat generation under an alternating magnetic field. Release studies showed that TA was released more slowly than TP under both passive and magnetically induced conditions, and that increased temperature improved both release kinetics and antiviral efficacy. Among the formulations tested, F2, which consitsted of extract E2 (with the highest TA content) and the highest extract loading (15.3%), exhibited the strongest antiviral activity. This formulation completely inhibited ASFV replication at a concentration of 250 ppm and an incubation temperature of 45 °C and achieved a 4.5 log10 reduction in viral titer. These results emphasize the potential of Fe₃O₄ plant extract nanosystems as a novel approach for ASFV inhibition in veterinary medicine.

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The citrate combustion technique was employed to synthesize barium hexaferrites represented by the formula BaFe_11.5Y_0.5O₁₉, where Y denotes Zr, Zn, Ni, and Gd. XRD analysis confirms the hexagonal structure of these materials, which are classified under the space group P63/MMC-(No 194). The smallest crystallite size is observed in BaFe_11.5Gd_0.5O₁₉, with measurements recorded at 36.968 nm according to the Halder-Wagner method. The band gap is calculated using the Tauc model. The introduction of dopant ions (Zr, Zn, Ni, and Gd) resulted in the establishment of electronic energy levels, which caused distortions in the sample and generated new locations for stabilizing charge carrier species within the samples. The BET plot shows H3 hysteresis with a type II isotherm, indicating that the inter-particle voids contribute to meso-porosity with an average pore diameter of 9.351 nm. The samples are applied in wastewater treatment, specifically serving as purifiers for lead-contaminated water. The impact of contact time is examined for all samples, revealing that BaFe_11.5Zr_0.5O₁₉ and BaFe_11.5Gd_0.5O₁₉ achieved the highest efficiencies of 99.693% and 99.237%, respectively. Moreover, BaFe_11.5Zr_0.5O₁₉ adhered to the intra-particle diffusion model, while BaFe_11.5Zn_0.5O₁₉, BaFe_11.5Ni_0.5O₁₉, and BaFe_11.5Gd_0.5O₁₉ correspond to the pseudo-second-order model, suggesting that the adsorption mechanism is primarily influenced by chemical processes.

With the rapid increase in electromagnetic wave (EMW) pollution, developing high-performance microwave-absorbing materials has become a critical priority. However, achieving effective absorbers with advanced structural properties and optimized multi-component compositions remains challenging. In this research, strong acids were used to surface-modify multi-walled carbon nanotubes (MWCNTs), oxidizing and yielding carboxyl groups on the surface. In situ polymerization applied to the multi-walled carbon nanotubes using a seeding method yielded the coating of polyaniline (PANI) on the MWCNTs uniformly. NiFe₂O₄ nanoparticles (NF NPs) were deposited on the polymerized MWCNT via a co-precipitation method. The particles were heat treated for 10 h at 230 °C to yield crystalline particles. In this research, ({rm{MWCNTs@PANI@NF}}) Nanocomposites (NCs) were synthesized with three different weight ratios of ({rm{polypyrrole}}) (({rm{PPy}})) : 20%, 40%, and 60%. Microscopic examinations showed that the NPs were evenly distributed across the nanotubes’ surface. TEM images determined the average size of the spherical NPs to be approximately 8.25 nm. VSM tests confirmed the ferromagnetic behavior of the samples after the heat treatment process, with a gradual decrease in saturation magnetization observed as the ({rm{PPy}}) weight ratio increased. To evaluate EMW absorption (EMWA) capabilities, the samples were tested in the X and Ku bands. The NC₃ sample recorded the highest reflection loss (RL) of -21.19 dB under the X band at d = 3.24 mm, and the same sample recorded RL values of -13.49 dB and -11.07 dB under the Ku band, both at the same thickness. These results demonstrated that ({rm{MWCNTs@PANI@NF@PPy}}) NCs, despite lower magnetization, showed superior EMW absorption performance compared to homogeneous composites. Due to advantages such as low weight, scalability for mass production, high stability, and recyclability, these NCs are recognized as innovative candidates for applications in microwave-absorbing materials.

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The current study investigates the fabrication of a dual Z-scheme photocatalytic system, i.e., FeCN/ZnSe/V₂O₅, to effectively remove Congo red (CR) dye. Recently, photocatalysis has gained popularity as a practical wastewater treatment approach due to using solar energy (a renewable energy source). All photocatalysts were synthesized using a simple and cost-effective method, such as thermal polycondensation and the hydrothermal method, to fabricate FeCN and ZnSe, respectively, while the calcination technique was used to construct bare V₂O₅. A physical mixing approach was used to form the binary and ternary heterojunctions of FeCN/ZnSe and FeCN/ZnSe/V₂O₅ heterojunction photocatalyst. By prolonging light absorption ability, lowering the recombination rate, and boosting charge separation efficiency, a dual Z-scheme route upgraded the photocatalytic performance of the ternary heterojunction photocatalyst. PL, EIS, and TPR investigations confirmed the lower recombination and higher charge transference in FeCN/ZnSe/V₂O₅ ternary heterojunction. The synthesized FeCN/ZnSe/V₂O₅ ternary heterojunction performed better photocatalytic efficiency towards CR degradation than other photocatalysts, 87% during 60 min of light irradiation. The ESR studies with scavenging investigations also established the crucial part of ^•O₂⁻ and ^•OH species during photodegradation. Also, recyclability experiments were performed to explore the stability of the synthesized ternary heterojunction photocatalysts, and ~78% removal efficiency was attained after 5 catalytic cycles, indicating its good reusability with stability.

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The increasing demand for sustainable energy solutions has driven significant interest in thermoelectric (TE) materials capable of converting waste heat into electricity. In the present study, we explore the effect of zinc (Zn) substitution on the thermoelectric properties of novel CoSb₂O₆ nanostructures synthesized via the sol-gel method. Structural analysis using X-ray diffraction (XRD) confirms the phase purity and hexagonal structure of the synthesized nanomaterials. In samples with increased zinc content, the formation of a secondary ZnO phase was observed. Field emission scanning electron microscopy (FESEM) reveals a nanoflower-like morphology composed of ~50 nm spherical particles. Thermogravimetric analysis (TGA) demonstrates excellent thermal stability up to 800 °C. Pelletized samples were evaluated for their thermoelectric performance over a range of temperatures. The electrical resistivity decreased with increasing Zn content, attributed to a rise in carrier concentration. The lowest resistivity was observed in the Zn₀.₁Co₀.₉SbO₆ composition, reaching a minimum value of 0.12 Ω·m. The Seebeck coefficient decreased with Zn substitution up to x = 0.1 but increased at x = 0.2, likely due to the formation of a ZnO secondary phase, which also led to an increase in resistivity. The optimized Zn₀.₁Co₀.₉SbO₆ sample exhibited the highest power factor of 1.3 μW·K⁻²·m⁻¹ at 533 K and a figure of merit (ZT) of 4 × 10⁻⁴ at the same temperature. These results highlight Zn substitution at the Co site as a promising strategy to enhance the thermoelectric performance of CoSb₂O₆-based materials.

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Fabricating thin films in a cost effective way is a key approach for technological advancement and for creating new materials for specific applications. This study presents an indigenously fabricated, programmable dip-coating unit for thin film fabrication, that can be used for photocatalytic applications. The dip coating unit integrates an arduino microcontroller and a stepper motor, providing adjustable control over withdrawal speed and dwelling time. With a total cost of approximately 10,000 INR, it serves as an economical and easily assembled alternative to conventional commercial systems. The performance of the dip coater, and hence the properties of deposited films was evaluated by varying withdrawal speed, dwelling time and by forming multilayer coatings. Optimum deposition condition was arrived at, for fabricating films with better photocatalyitic activity. Photocatalytic efficiency of optimized thin film sample under sunlight was assessed by using methylene blue as model pollutant, yielding an efficiency of 79.35% in 90 min at the first cycle of photocatalysis. Reusability of the photocatalyst was confirmed by evaluating activity of the film for four cycles. The fabricated dip coating unit is thus found capable of depositing high quality thin films suitable for effluent remediation.

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