Journal of Sol-Gel Science and Technology最新文献

In this study, films with compositions of 75 mol.%SnO₂-15 mol.%ZnO-10 mol%Fe₂O₃ and 60 mol.%SnO₂-20 mol.%ZnO-20 mol%Fe₂O₃ were deposited onto alumina substrate starting from gels prepared via the sol-gel method, for gas sensing applications. The films were thoroughly characterized using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), UV-Vis spectroscopy, and electrochemical impedance spectroscopy (EIS). XRD analysis confirmed the films exhibited slight crystallization of SnO₂, while SEM images revealed a homogeneous structure with microcracks, which were more prominent in the film with lower Fe content. The surface chemistry investigations assessed by X-ray Photoelectron Spectroscopy (XPS) showed the presence of Sn⁴⁺, Zn²⁺, and Fe³⁺ ions on the surface, confirming successful incorporation of these in good agreement with XRD and Raman spectroscopy. UV-Vis spectroscopy indicated that the band gap decreased with increasing Fe content, suggesting tunable optical properties. The films were tested for their gas sensing performance using electrochemical impedance spectroscopy, demonstrating sensitivity to propane with a significant response at 400 ppm and optimal performance at 300 °C.

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In the present study, we have explored the design of heterojunction nanocomposites, focusing on and abundant availability. In this work, Cobalt Oxide–Copper Oxide (Co₃O₄–CuO), a p–p heterostructure with complementary electronic properties, was synthesized via a facile sol–gel route followed by calcination. The material was systematically characterized by XRD (X-ray diffraction), FTIR (Fourier Transform Infrared), XPS (X-ray Photoelectron spectroscopy), SEM-EDX (Scanning electron microscope-Electron diffraction X-ray), TEM (Transmission electron microscope), UV–Vis (Ultraviolet visible), PL (photoluminescence) spectroscopy, and BET (Brunauer-Emmett-Teller) to establish their structural, morphological, and optical and surface features. The NC exhibited a narrowed band gap of 2.18 eV compared to pristine oxides, suggesting enhanced light-harvesting capability. Photocatalytic experiments under UV irradiation revealed that the Co₃O₄–CuO heterojunction achieved nearly complete degradation of Brilliant Blue G (BBG) dye within 120 min of irradiation, with a pseudo-first-order kinetic rate constant (0.030 min^–1) markedly higher than that of individual Co₃O₄ and CuO. The superior performance was attributed to efficient charge separation at the heterojunction interface, suppressed electron–hole recombination, and the dominant role of superoxide radicals (^•O₂⁻) as reactive oxidative species. Electrochemical studies further validated improved conductivity and lower charge transfer resistance of the nanocomposite. Additionally, regeneration tests confirmed excellent structural stability and reusability over multiple cycles. This study underscores the significance of engineering binary transition-metal oxide heterojunctions as cost-effective and scalable photocatalysts for wastewater treatment.

The spinel MgFe₂O₄ ferrite was synthesized using a sol-gel auto-combustion technique at 650 °C, 750 °C, and 1050 °C for 4 h. Instrumental techniques including Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometry (VSM), Mössbauer spectra and low frequency dielectric measurements were used for characterization of heated samples. The absorption bands in the wavenumber range of 531–400 cm^–1 for all samples are due to the Fe³⁺ - O^2- stretching vibrations. XRD analysis of all samples were consistent with a pure spinel phase with crystallite size of 28 nm to 38 nm, except the sample heated at 650 °C which exhibited a small quantity of α-Fe₂O₃. SEM analysis showed that the morphology changed with heating temperature. Dielectric studies of all samples within the frequency range 100 Hz to 2 MHz at room temperature indicated frequency-dependent phenomena. Furthermore, its application in dye sensitized solar cells was also explored, with a 4.2% power conversion efficiency obtained.

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The excessive Utilization of fossil fuels is increasing energy shortage as well as several environmental issues. Sustainable and renewable energy systems are essential for the production of cost-effective electro-catalysts that exhibit long-term durability and superior electrocatalytic performance to improve oxygen evolution reaction (OER). Delafossite oxide was recently discovered as a viable alternative to the precious metal catalysts of RuO₂ and IrO₂. They can serve as highly efficient electrocatalysts in OER. This study used a low-cost, simple hydrothermal method to fabricate CuCoO₂-supported g-CN, which was then characterized utilizing scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The CuCoO₂/g-CN nanomaterials were analyzed in a 1.0 M KOH solution using several electrochemical methods. Additionally, the kinetic mechanisms of CuCoO₂/g-CN composite electrocatalyst were examined using LSV, chronoamperometry, CV, and EIS to assess stability and performance of the catalytic mechanism. Electrochemical results show a significant overpotential of 197 mV at 10 mA cm⁻² C_d and a Tafel value of 34 mV dec⁻¹, lower Rct (2.74 Ω), and greater stability for 30 h. As a result, manufactured material performs exceptionally well in the OER procedure and in a variety of potential devices.

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This article discusses how to experimentally manufacture a suitable and required material combination as an active material (Gain Medium) for lasers made by optical microcavities. Here, the selected materials are Cr³⁺:Al₂O₃–Ruby Nanoparticles (NPs) because of the successful laser applications of ruby lasers in macroscopic dimensions. Here, there was a desire to investigate the laser performance of ruby particles in nanometer dimensions. These particles were made at interval of two years and in two different stages in the chemistry laboratory, first by the sol-gel method and then by crushing with a high-speed homogenizer as a creative and innovative approach. The minimum size of the particles in the smallest scale resulting from both methods is around 15 nm. X-ray Diffractometer (XRD) analysis was used to check the crystallinity of the particles, phase of the structure, and their constructive elements. Photoluminescence spectroscopy (PL) analysis was used to check the luminescence properties of ruby nanoparticles. Also, Transmission Electron Microscopy (TEM) characterization was performed for each reduction step in the size of ruby particles. Results show these ruby (NPs) dimensions exhibit unique properties that are fully mentioned in the text. Therefore, they can be applied as a professional optical microcavity gain medium.

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Biofilm formation enhances bacterial resistance, posing major challenges in infection control. This study developed biocompatible magnetite (Fe₃O₄) nanoparticles with improved antibiofilm activity. Fe₃O₄ nanoparticles were synthesized via a hydrothermal method and functionalized with gum Arabic (GA) and folic acid (FA). XRD confirmed a pure cubic spinel structure, while FTIR verified successful surface modification. FESEM revealed quasi-spherical, well-dispersed particles, and UV–Vis analysis showed slight shifts in optical absorption after functionalization. VSM results indicated soft magnetic behavior, with increased saturation magnetization in FA-coated samples and a slight reduction in GA-coated ones. Hemolysis assays confirmed good biocompatibility (<5% hemolysis at 100–400 µg/mL). In combination with H₂O₂, FA-coated Fe₃O₄ nanozymes exhibited the highest inhibitory effect against Pseudomonas aeruginosa and Staphylococcus aureus biofilms. These findings demonstrate that surface functionalization effectively enhances the magnetic, catalytic, and antibiofilm properties of Fe₃O₄ nanoparticles.

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Efficient and scalable synthesis of nanostructured pseudocapacitive materials is crucial for the development of high-performance energy storage systems. In this work, manganese (hydro)oxides were synthesized using a continuous-flow microreactor equipped with intensive counter-current swirling flows, ensuring enhanced micromixing and precise control over reaction kinetics. By varying the reagent flow rates (1.5, 2.2, and 3.0 L/min), the phase composition, crystallinity, and porosity of the resulting materials were effectively tuned. Powder X-ray diffraction, Raman spectroscopy, and EDX analysis revealed a phase evolution from Mn(OH)₂ and MnOOH at lower flow regimes to highly crystalline Mn₃O₄ spinel at 3.0 L/min. SEM and BET analysis confirmed the formation of layered mesoporous structures with surface areas up to 120 m²/g. Electrochemical characterization in 1 M Na₂SO₄ demonstrated a strong correlation between synthesis conditions and capacitive performance. The best-performing electrode (MR-3.0) exhibited a specific capacitance of 200 F/g at 5 A/g, low charge-transfer resistance, and ideal capacitive behavior. These enhancements are attributed to optimized ion transport and enhanced accessible surface area resulting from flow-assisted synthesis. Overall, the results highlight the potential of swirling-flow microreactors as a robust platform for producing advanced pseudocapacitive materials with tunable properties, suitable for next-generation supercapacitor electrodes in hybrid energy storage systems.

This comparative study analyzes crystallite size, strain, BET surface area, pore size, dielectric properties, and AC conductivity of double perovskite compositions: La₂NiMnO₆ (LNMO), La₂CuMnO₆ (LCMO), and La₂ZnMnO₆ (LZMO), synthesized via Sol–Gel Pechini route. X-ray diffraction confirmed monoclinic structures (P2₁/n). Williamson-Hall analysis showed LNMO with the smallest crystallite size (55.71 nm) and the highest strain (3.24 × 10⁻³), while LCMO has the largest size (64.22 nm) and the lowest strain (1.43 × 10⁻³). BET analysis indicated LZMO with the highest surface area (6.673m²/g), and LNMO with the smallest pore size (3.038nm). LCMO exhibited the highest dielectric constant, suggesting a strong potential for energy storage applications, with an inverse correlation between dielectric constant and BET surface area. However, the higher tangent loss for LNMO and LCMO limits their practical applications in low-loss devices. Impedance spectroscopy revealed non-Debye-like relaxation. LCMO also showed the highest AC conductivity, attributed to enhanced charge carrier hopping among Cu/Mn cations. The highest activation energy for LZMO aligns well with the lowest conductivity, highlighting its insulating and semiconducting applications. The study emphasizes the effects of transition metal cations at the M-site, providing a detailed comparison of the compositions.

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This study presents the first systematic investigation of zinc-doped barium copper aluminum ferrite (Zn_XBa_0.8-xCu_0.2Al_0.7Fe_1.3O₄, (X = 0, 0.2, 0.4, 0.6)) nanocomposites, demonstrating unprecedented multi-element synergistic effects. The nanocomposites were synthesized via sol-gel auto-combustion and characterized using X-ray diffraction (XRD), Fourier-transform infrared (FTIR, SEM-EDX, BET, scanning electron microscopy-energy dispersive X-ray (SEM–EDX), Brunauer–Emmett–Teller (BET), and other techniques. The novel findings revealed that increasing the Zn content systematically decreased the crystallite size (from 35.746 to 24.197 nm) and reduced the lattice parameters (from 8.4625 to 8.3915 Å), indicating successful Zn incorporation into the spinel structure. BET analysis showed an increase in the surface area (18.86 to 43.75 m²/g) and pore volume (0.039 to 0.088 cm³/g) with increasing Zn concentration in the catalyst. Remarkably, the optimized Zn₀.₆Ba₀.₂Cu₀.₂Al₀.₇Fe₁.₃O₄ catalyst achieved 97.67% tetracycline degradation efficiency within 140 min, a significant improvement over undoped ferrites (66.70%), with superior quantum efficiency (1.25 × 10⁻⁶ molecules/photon) and space-time yield (1.25 × 10⁻⁷ molecules/photon). The broad-spectrum efficacy of the catalyst was demonstrated by the effective degradation of diverse pollutants: ciprofloxacin (87.34%), atrazine (84.54%), methylene blue (63.56%), and methyl orange (52.54%). Breakthrough performance was achieved when combined with peroxymonosulfate (PMS), enabling complete tetracycline removal within 40 min, compared to persulfate (120 min) and hydrogen peroxide (80 min). Mechanistic studies identified superoxide and hydroxyl radicals as the primary reactive species, and exceptional stability (78.23% activity retention after eight cycles) was demonstrated. These findings address the critical global water scarcity challenges affecting 2.3 billion people, offering a sustainable solution for pharmaceutical wastewater treatment through innovative multi-element catalyst designs.

The development and optimisation of silica-cork aerogel composites, prepared with tetraethyl orthosilicate (TEOS) and vinyltrimethoxysilane (VTMS) as co-precursors and reinforced with short cut aramid fibres is herein presented. Different synthesis parameters, such as co-precursor ratio, amount of fibres, and cork granulate dimensions, were investigated using a design of experiments approach to obtain composites with lower bulk densities and thermal conductivities. The obtained materials presented densities ranged from 0.140 to 0.190 g cm⁻³ and thermal conductivities in the superinsulation range (16.6–19.1 mW m⁻¹K⁻¹). These features, combined with their flexibility and thermal stability up to 300 °C, make the produced composites promising candidates for high-end applications in the automotive, buildings, and space industry, where high-performance insulation materials are needed. Also, the produced samples present sound absorption performance which expands their applicability to double barrier purpose, for heat and sound. Moreover, the composites exhibited excellent flame resistance after a qualitative test, even achieving flame extinction, positioning them as promising candidates for applications in the building industry. By utilizing renewable cork resources and improving energy efficiency, these materials can contribute to the reduction of environmental impact of insulator materials and will promote sustainable development in multiple sectors.