Journal of Sol-Gel Science and Technology最新文献

The sol–gel method is a powerful route for producing ceramics, glasses, and hybrid nanostructures; however, conventional sol–gel processing remains limited by long reaction times, high-temperature treatments, and the use of toxic organic solvents. This review evaluates the hypothesis that combining eco-efficient strategies with accelerated sol–gel routes can significantly improve sustainability and synthesis efficiency while maintaining or enhancing material performance. Reported studies show that eco-efficient formulations can reduce solvent-related hazards and VOC emissions, in some cases approaching reductions of 70–90% depending on the solvent system and precursor chemistry. Processing times have also been shortened substantially, with several reports documenting the reduction of gelation or drying steps from hours to minutes under optimized microwave or ultrasound activation. These quantitative trends are summarized in the revised Table 2 and detailed in the Supplementary Information. These rapid routes also produce hybrid nanomaterials with 20–40% smaller particle sizes, higher homogeneity, and improved optical and catalytic behavior. Emphasis is placed on inorganic–polymer, bioactive glass–biopolymer, and carbon-based hybrid systems, which exhibit enhanced mechanical stability, biocompatibility, and functional versatility. Comparative analysis with conventional sol–gel processes highlight the key advantages, existing gaps, and application relevance in energy, environmental remediation, and biomedical fields. This review provides a concise and up-to-date reference for researchers seeking sustainable, energy-efficient, and high-performance sol–gel strategies for advanced hybrid nanomaterial design.

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Rare-earth metal oxides have gained significant attention as promising electrode materials for energy storage due to their exceptional electrochemical properties. In this study, a nanocomposite comprising cerium oxide (CeO₂) and lanthanum oxide (La₂O₃) was synthesized via a microwave-assisted sol-gel method, followed by post-annealing, tailored for supercapacitor applications. Structural and morphological analyses confirmed the successful formation of nanocomposites with beneficial characteristics. Further investigations into surface area and pore structure revealed that the incorporation of lanthanum oxide greatly enhanced the material’s electrochemical activity. Electrochemical evaluations revealed a specific capacitance of 1038 Fg⁻¹ at 1 Ag⁻¹ and 994 Fg⁻¹ at 1 mV s⁻¹, obtained from galvanostatic charge-discharge and cyclic voltammetry, respectively. These results demonstrate superior electrochemical performance compared to pristine CeO₂, highlighting the enhanced charge storage capability and excellent rate performance of the CeO₂-La₂O₃ composite. An asymmetric all-solid-state supercapacitor, utilizing the CeO₂-La₂O₃ composite as the positive electrode and activated carbon as the negative electrode, achieved an energy density of 18 Whkg⁻¹ and a power density of 1500 Wkg⁻¹. Additionally, the device showcased remarkable cyclic stability, retaining 98% of its capacitance over 10,000 cycles. These findings underscore the significance of lanthanum oxide in enhancing cerium-based systems, presenting promising opportunities for next-generation energy storage technologies.

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In this research, a series of copper-substituted X-type hexaferrite with chemical composition Sr_2-x Ni₂Cu_xFe₂₈O₄₆ (x = 0.0 to 1.0, Δx = 0.2) was prepared. XRD analysis confirmed the formation of the X-type phase along with W-type (both of which are hexagonal) and hematite (an orthorhombic) phases. FTIR analysis revealed three distinctive absorption bands spanning in the range of 410 cm⁻¹ to 510 cm⁻¹. These bands are attributed to the stretching vibrations of Fe³⁺- O²⁻, consistent with the formation of the ferrite phase. FESEM micrographs show agglomerated hexagonal plate-like structures with the small polygonal grains spread over the surfaces of these plates. The average grain size increased from 0.5 (mu m) to 3.4(,mu {m}) with increasing Cu content up to x = 0.8. Magnetic hysteresis loops of all prepared compositions show a soft magnetic nature (coercivity- H_c < 500 Oe). Saturation magnetization (M_s) and remanent magnetization (M_r) values decreased with increasing Cu-content from x = 0.2 to 1.0. The reduced remanence observed in the substituted compositions opens up exciting avenues for the utilization of copper-substituted Ni₂X-hexaferrites in transformer cores, inductors, electromagnetic shielding, and magnetic sensors.

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The discovery and development of efficient photocatalytic materials for environmental applications is a rapidly evolving research area. This work addresses the photo degradation of RhB 6 G, a fluorescent dye, utilizing a novel heterogeneous catalyst: lanthanide metal-doped Co₃O₄. Pristine Co₃O₄ was produced using chemical sol-gel and green synthesis with Azadirachta indica leaves (Neem leaf) extract. The catalysts’ structural, morphological, and optical characteristics were investigated using XRD, FT-IR, FE-SEM, HR-TEM, UV-DRS, RAMAN, BET, XPS, and PL analysis. The average diameters of the crystallites were found to be 11.47 nm (Ce-doped), 41 nm (green), and 45 nm (chemical). Based on Tauc plots, the corresponding band gap energies were 2.42 eV, 2.8 eV, and 2.9 eV, respectively. The Ce@Co₃O₄ catalyst’s surface area increased significantly, according to the BET study (96.2 m²/g), and PL analysis revealed lower emission intensity, which suggests suppressed charge carrier recombination. Additionally, XRD-based microstructural analysis revealed that Ce@Co₃O₄ exhibited the highest dislocation density and microstrain, suggesting a higher density of structural defects that may facilitate more efficient charge separation and enhanced surface reactivity. The degradation of RhB 6G under direct sunlight irradiation was used to determine photo-catalytic activity. Various parameters, such as reaction conditions, reactive species identification, mechanism, and the effects of competing species, were investigated. After 75 min of exposure to sunlight, the doped catalyst degraded by an astonishing 94%. The kinetic study confirmed that the pseudo-first order model is followed with a rate constant of 0.0541 min^-1. An additional dimension to its multifunctional potential was added when Ce-doped CoO₄ showed strong antibacterial activity, especially against E. coli, because of increased reactive oxygen species production. The Ce@Co₃O₄ composite holds great promise as a material for the degradation of diverse pollutants and antibacterial activity in future applications.

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Environmental contamination by various pharmaceutical materials has far reached negative impacts on the lives of human beings. Therefore, multiple strategies has been adopted to eliminate these contaminants from the water bodies. One of these strategies is the use of composite materials, therefore ternary composite has been designed to mitigate ciprofloxacin (CFX). In order to synthesize desired ternary composites initially Bi₂WO₆/BiOX binary composite and Bi₂O₃ were synthesized by hydrothermal approach and their equimolar ratios were used to prepare ternary composites using ultrasonication method. The structural and morphological properties were confirmed by powder XRD and FE-SEM analysis. The elemental composition and functional group detection were carried out using EDX and FT-IR spectroscopy. Further, UV-visible and PL spectroscopy were used to understand the optical properties of the ternary composites. BET analysis was used to figure out surface area and porosity of the most active composite material. In addition, the Bi₂O₃/Bi₂WO₆/BiOX exhibit an enhanced photocatalytic potential for the degradation of CFX due to heterojunction, which improved the light absorption ability and e^–/h⁺ pairs separation efficiency. Even after several times use the Bi₂O₃/Bi₂WO₆/BiOX material had rather high activity and stability. Further, the photocatalytic degradation was fine-tuned by varying halogens in BiOX which is the part of ternary composite. The photocatalytic degradation rate over ternary composites Bi₂O₃/Bi₂WO₆/BiOCl (BWO-Cl), Bi₂O₃/Bi₂WO₆/BiOBr (BWO-Br) and Bi₂O₃/Bi₂WO₆/BiOI (BWO-I) are 92.61%, 90.14% and 87.88%, respectively. The kinetic studies confirmed that BWO-Cl followed pseudo first order reaction kinetics scavenging tests confirmed that superoxide radicals (·O²⁻) and holes (h⁺) are the key reactive species in degradation reaction of CFX. In this work all bismuth based compounds were used for the development of bismuth based ternary composites which intern enhanced the visible light driven photocatalytic degradation of CFX.

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The remarkable structural properties and diverse functional applications have made ferrite a well-recognized material. Due to their magnetic properties, in the past few years these materials have been recognized for their uses in energy storage, catalysis and environmental applications. In our study, we have fabricated Ni-Mg-mixed spinel ferrites i.e., Ni_0.5Mg_0.5Ga_xFe_2-xO₄ (x = 0.00. 0.01, 0.02, 0.03) with different dopant content of gallium by sol-gel auto-combustion route. The crystalline nature with Fd3m space geometry is found by XRD. The morphological study showed the nano structured material having grain size distribution in nano-range. With Ga doping, a decrease in energy band is observed from 1.35 to 1.07 eV, whereas the surface area expands from 7.7 to 9.7 m²/g. The magnetic study confirms the ferromagnetic behavior of pure and doped Ni-Mg ferrites. The CV analysis showed that the highly doped NM2 sample exhibits the highest capacitance retention at 74% at 80 mV s⁻¹. The GCD study show that the NM2 sample demonstrates the highest capacitance retention rate of 97% at 8 A g⁻¹. Thus, the current research study shows that the mixed spinel ferrites can be highly recommendable candidate for supercapacitor applications.

The growing resistance of the pathogenic bacteria to traditional antibiotics has provoked a strong demand of the new antimicrobial materials. Silver nanoparticles (AgNPs) have emerged as potent candidates due to their broad-spectrum antibacterial activity and tunable physicochemical properties. This study presents a systematic research on how the reaction parameters affect the formation, structure and antibacterial behavior of silver nanoparticles (AgNPs) prepared through a straightforward chemical reduction method. Five AgNP formulations (S1–S5) were prepared by varying reaction temperature and time, using sodium dodecyl sulfate (SDS) as a stabilizer and hydrazine hydrate as a reducing agent. UV–visible spectroscopy and XRD analyses were performed for all synthesized samples to examine the effect of synthesis conditions on the optical and structural evolution of AgNPs. The optimized sample (S4, 70 °C, 60 min) was subjected to comprehensive microstructural and surface characterization through SEM, TEM, EDS, and FTIR analyses to establish a clear structure–property relationship. The UV–Vis spectra exhibited distinct surface plasmon resonance (SPR) bands in the range of 395–420 nm, red-shifting systematically with increasing reaction temperature and time, confirming particle growth and enhanced crystallinity. XRD analysis revealed the formation of highly crystalline face-centered cubic (FCC) silver with increasing phase purity under optimized conditions. SEM and TEM imaging of the optimized sample revealed spherical nanoparticles in the range of 60–75 nm, while EDS confirmed compositional purity and uniform spatial distribution of silver. Antibacterial evaluation against Escherichia coli and Staphylococcus aureus revealed that AgNPs prepared at 70 °C for 60 min exhibited the highest efficiency, with minimum inhibitory concentrations (MICs) of 25 µg/mL and 50 µg/mL, respectively. A weak DPPH radical scavenging activity was also observed, reflecting moderate antioxidant potential. The findings demonstrate that the increased crystallinity and homogeneous microstructure of the AgNPs are the direct factors determining their antibacterial effectiveness. This enhanced performance is attributed to improved Ag⁺ ion release and stronger interaction of well-crystallized, uniformly shaped nanoparticles with bacterial cell walls, resulting in more effective disruption of cellular integrity. Overall, this study establishes a direct correlation between synthesis parameters, structural evolution, and biological performance, providing a reliable framework for the rational design of functional AgNPs.

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Transition metal oxides have emerged as promising candidates for electrochemical energy storage devices, such as batteries and supercapacitors, due to their versatile redox properties. However, challenges related to low energy density and limited cycling stability remain. In this study, MoO₃ (MO) and zinc (Zn)-MoO₃ (Zn-MO) nanoflakes were successfully synthesized via a hydrothermal method. The Zn-MO nanoflakes exhibited significantly enhanced electrochemical performance compared to pristine MO, achieving a high specific capacity of 82.7 mAh g⁻¹ and a capacitance of 647.8 F g⁻¹ at a current density of 2 A g⁻¹. Remarkably, after 10,000 charge–discharge cycles, the Zn-MO electrode retained 98% of its initial capacity with 99% coulombic efficiency. Furthermore, a pouch-type hybrid supercapacitor (HSC) was assembled using Zn-MO and activated carbon, delivering an energy density of 26.07 Wh kg⁻¹ and a power density of 5120 W kg⁻¹. The device demonstrated excellent cycling stability (90%) and high coulombic efficiency (99%), highlighting its practical applicability for real-world energy storage applications.

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The green synthesis of metal oxide nanoparticles has emerged as a sustainable and eco-friendly alternative to conventional chemical methods. Utilizing plant-derived phytochemicals as natural reducing and stabilizing agents, this approach eliminates hazardous chemicals and energy-intensive processes. Beyond environmental benefits, green synthesis influences the physicochemical and biological properties of nanoparticles by enhancing surface functionality, stability, and bioactivity. Zinc oxide nanoparticles are widely favored in biomedical applications due to their biocompatibility, affordability, and low toxicity. Their therapeutic effects, especially in anticancer and antibacterial applications, arise from their ability to generate reactive oxygen species, release Zn²⁺ ions, and induce apoptosis. This study synthesized ZnO NPs via chemical and green routes using aqueous extracts from Medicago sativa, Euphorbia milii, Codiaeum variegatum, and Helianthus annuus. Structural analysis confirmed that green synthesis did not alter the ZnO crystalline structure. However, biological activities varied significantly by plant extract. Codiaeum variegatum-mediated ZnO NPs showed superior antioxidant activity (60.8% DPPH scavenging) and strong cytotoxicity against A549 lung cancer cells (94.7% reduction). Chemically synthesized ZnO NPs exhibited notable anti-inflammatory activity (90.4%). ZnO NPs from Medicago sativa demonstrated potent antidiabetic effects via α-amylase (86.5%) and α-glucosidase (85.7%) inhibition. All ZnO NPs inhibited the growth of Escherichia coli, Klebsiella pneumonia, Streptococcus pyrogenes, and Staphylococcus aureus with maximum MBC value 47.4 mg/ml of chemogenic ZnO NPs against S. aureus and 44.4 mg/ml for biogenic ZnO NPs against S. pyrogenes. Additionally, Medicago sativa ZnO NPs recorded the highest suppression of S. pyogenes biofilm formation by 79%. The obtained results highlight the role of green synthesis as an effective strategy to tailor ZnO NP bioactivity for biomedical applications.

One important area of study that needs to be addressed right now is the development of energy storage systems with high energy density (E_d) and broad stability. Given these needs, it was important to note that supercapacitors (SCs) show a lot of promise as workable solutions for meeting these needs. To verify the crystallinity, morphological, functional group, and elemental composition of the produced hybrid material, it was physically characterized using a variety of methods, including X-ray diffraction, scanning electron microscopy, Fourier Transform infrared spectroscopy, and energy dispersive X-ray spectroscopy. An electrochemical investigation of Bi-doped ZnFe₂O₄ was examined, which confirmed the specific capacitance (C_sp) of 1537.03 F g⁻¹ obtained at 1 A g⁻¹. Also, Bi-doped ZnFe₂O₄ demonstrates 109.80 Wh kg⁻¹ energy density (E_d) and 680.4 W kg⁻¹ power density (P_d) and outstanding stability inside 3.0 M KOH across 10000^th cyclic CV studies. The R_s values of the undoped ZnFe₂O₄ and Bi-doped ZnFe₂O₄ are 0.85 Ω and 0.74 Ω, consequently. The better electrochemical efficiency is achieved by the Bi-doped ZnFe₂O₄ material’s higher surface area (52 m² g^-1) evaluated to ZnFe₂O₄ (37 m² g^-1), broad active area, and reduced resistance. Our study has confirmed that the produced substance can improve the spinel-structured transition-metal oxides’ capacitive qualities in newly developed energy storage devices.

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