Journal of Sol-Gel Science and Technology最新文献

Copper doped nickel-zinc ferrites nanoparticles with formula Cu_XNi_(0.5-X)Zn_0.5Fe₂O₄ where, X = 0.0, 0.1, 0.2, and 0.3 were successfully synthesized using a facile and rapid sol-gel technique at room temperature. X-ray diffraction studies were performed to assess the crystallinity and phase purity, revealing the formation of well-defined single phase spinel nanostructures. The variation in Cu concentration appeared to influence lattice properties and crystallite sizes, exhibiting as these ions were successfully incorporated into the spinel lattice. The change in grain size with evolving x values reveals that the Cu substitution levels play a pivotal role in the ferrite nanoparticles sintering and growth process. The electrical conduction mechanism in ferrites is predominantly attributed to electron migrating among Fe(II) and Fe(III) ions onto octahedral (B) sites of spinel nanostructures. This route is influenced by the proportions of divalent and trivalent iron ions, which are additionally affected by Cu substitution levels. The regular variation in copper content in nickel zinc ferrite has significant implications for the material’s structural, electrical, and magnetic characteristics. Structural changes, especially changes in the lattice constant and particle size, are accompanied by variations in electrical conductivity, which are modulated by the hopping process of mixed-valence iron ions. The magnetic characteristics are further impacted by magnetic interactions between cations onto both tetrahedral (A) and octahedral (B) sites, which are modified by varying the concentration of substituent ions. This work sheds light on how controlled doping may be used to alter the multifunctional attributes of ferrite nanoparticles for possible applications in magnetic, electrical, and catalytic sectors.

Spintronics, which merges principles of magnetism and electronics, has emerged as a transformative field with the potential to revolutionize data storage, logic devices, and quantum technologies. Metal oxide nanostructures synthesized via sol–gel techniques are particularly promising for spintronic applications due to their low-cost fabrication, tunable structures, and magnetic functionalities. This mini-review summarizes recent advances in sol–gel-derived magnetic metal oxides, including transition-metal-doped TiO₂, La_1−xSr_xMnO₃, Co-doped ZnO, and Fe₃O₄, focusing on their synthesis, structural control, and room-temperature ferromagnetism. The influence of the sol–gel process on dopant distribution, grain boundary effects, and defect-mediated magnetism is discussed in detail. Key spintronic properties such as magnetoresistance, spin polarization, and magnetodielectric behavior are highlighted, along with current challenges in reproducibility and phase purity. Finally, the review outlines future directions for integrating sol–gel-derived metal oxides into practical spintronic devices, aiming to connect sol–gel chemistry with condensed matter physics and provide guidance for researchers at the intersection of materials science and spintronics.

In this novel research, an effective S-scheme Bi₂O₂CO₃/TiO₂ heterostructure was constructed by coupling TiO₂ with various proportions of Bi₂O₂CO₃ for mitigating rhodamine B dye under commercial visible LED lamp. Mesoporous Bi₂O₂CO₃/TiO₂ heterojunction with 10 wt% Bi₂O₂CO₃ nanoparticles were generated via sonochemical method. Through the employment of DRS, XPS, SEM, PL, HRTEM, XRD, SEM, EDX and N₂-adsorption-desorption isotherm, the complete characterization of the specimens was evaluated. Photoluminescence analysis recorded that the transportation rate of electron-hole pairs of TiO₂ has been strongly promoted after being hybridized with Bi₂O₂CO₃ nanoparticles. The experimental results revealed that Bi₂O₂CO₃ recorded a crucial role in both photocatalytic activity and light harvesting of titania by depressing the optical band gap energy and elevated the surface parameters to more positive direction. The heterojunction with 10 wt% Bi₂O₂CO₃ improved and optimized the photocatalytic activity which destroyed 85.5% of RhB dye during 240 min of exposure to visible radiation with kinetic rate of 0.0082 min⁻¹.The pronounced improvement in the photocatalytic efficiency of Bi₂O₂CO₃/TiO₂ heterojunctions was attributed to the proper production of an auspicious S-scheme heterostructure with strong redox capability, employing reactive species OH^. and O₂^.- radicals in the photocatalytic reaction. PL spectrum of hydroxyterephthalic acid and reactive oxygen trapping experiments implied that S-scheme pathway was the appropriate model for elucidating the mechanism of the charge transfer mechanism between TiO₂ and Bi₂O₂CO₃ semiconductors.

The proliferation, differentiation or viability of cells on a bioactive surface such as ß-tricalcium phosphate (ß-TCP) is a key aspect of regenerative medicine and biomaterials research. In this study, a sol-gel solution specifically developed for biomaterial applications was used, into which crystalline ß-tricalcium phosphate (ß-TCP) powder was added at various concentrations. This approach differs from conventional methods where ß-TCP is synthesized directly within the sol–gel matrix. The direct incorporation of powder into the base sol allows for better control over particle distribution and size, influencing the morphology, mechanical properties, and biological activity of coatings applied to titanium substrates. The surfaces were characterized in terms of changes in roughness, wettability, and mechanical parameters. Biological tests with the MG63 cell line showed increased cell proliferation and adhesion, particularly during the first 48 h of cultivation, confirming the bioactive effect of the added ß-TCP powder. These results suggest the potential of this approach for developing bioactive coatings on titanium implants with improved osseointegration and stability.

Environmental damage and current energy crisis have intensified global shift toward clean energy resources and sustainable to reduce dependence on fossil fuels. Among various strategies, water splitting has emerged as an efficacy process for sustainable H₂ generation. However, slow reaction rate of oxygen evolution reaction (OER) significantly hampers overall efficiency. In this work, a NiFe₂O₄/g-CN nanocomposite was fabricated via a hydrothermal route to enhance OER performance. The composite exhibited a unique structural morphology, where NiFe₂O₄ nanoparticles were well-dispersed across the g-CN nanosheets, offering a more active spots and higher surface area (SA) for electrolyte interaction. Compared to pure NiFe₂O₄, the NiFe₂O₄/g-CN electrode demonstrated superior catalytic behavior, achieving a reduced overpotential (ɳ) of 198 mV at a current density (j) (10 mA cm⁻²), along with excellent operational stability over 20 h. Furthermore, the electrocatalyst exhibited a high electrochemically active surface area (ECSA) of 752.5 cm² and a favorable overpotential (η) 198 mV and Tafel gradient of 33 mV dec⁻¹. The enhanced OER performance was attributed to synergistic interaction among NiFe₂O₄ and g-CN, which facilitates efficient charge transport. Additionally, the electronic structure of NiFe₂O₄/g-CN contributes to improved reaction kinetics, making this composite a promising and low-cost alternative to noble metal-based OER electrocatalysts. This work highlights the potential of NiFe₂O₄/g-CN as a highly efficient electrode sample for future energy conversion and storage characterizations.

Magnesium (Mg) based implants are acquiring fame in biomedical fields, particularly where biodegradable materials are desired to eradicate the need for a second surgery. The materials are employed for short-term implants, especially in orthopedics and cardiovascular stents, as they can reduce hospitalization time and associated expenses. From a material standpoint, their lightweight, high strength-to-weight ratio, ease of manufacture, excellent biocompatibility, and biodegradability offer distinct advantages, making them suitable for temporary implants. Nonetheless, their primary challenge stems from their susceptibility to corrosion within physiological environments. This work reported silica (Si) and silica-hyaluronic acid (Si/HA) coating on AZ31 Mg alloy that enhances corrosion resistance and biocompatibility. The Si/HA-coated substrate demonstrated a three-dimensional porous structure, resulting in an intermediate degradation rate, higher than the Si-coated substrate and lower than the uncoated substrate. The amino acids of HA induced a biomineralized layer facilitating a significant hike rate of calcium and phosphate ions, forming a halloysite-like structure. The hemocompatibility and cell adhesion were supported by Si/HA-coated substrate along with effective bacterial inhibition. On the whole, Si/HA-coated Mg substrate can be employed in healthcare applications where biodegradability and biological performance are vital.

The study of Fe-containing catalytic systems in the carbon dioxide hydrogenation reaction was conducted. A series of systems on the basis of iron oxide Fe₂O₃ wiśthout the addition of a second component and with the addition of aluminum (Al₂O₃), cerium (CeO₂), zirconium (ZrO₂) or silicon (SiO₂) oxides was synthesized. Each system was synthesized by two methods, analogous to mesoporous molecular sieves synthesis methods for MCM-41 and SBA-15 with the use of cetyltrimethylammonium bromide and Pluronic 123 templates. The resulting samples had a uniform distribution of components on the surface with a component ratio close to 1:1 and iron oxide crystallite sizes ranging from 7 to 23 nm. The highest activity in the reaction of hydrogenation of carbon dioxide was demonstrated by the sample Fe/Al with Pluronic 123 as a template, the conversion was 11.5%, and the formation of mesopores with a maximum diameter of 15 nm was observed in the sample.

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ZnO/ZnO₂ nanocomposite thin films were obtained by doping ZnO with silver using a cost-effective sol–gel spin coating technique to investigate the impact of Ag concentration on their physical properties. The nanocomposite thin films were prepared by introducing silver into a zinc oxide precursor solution made from zinc acetate dihydrate, with doping levels systematically varied from 0 to 5 wt%, and deposited on glass substrates. X-ray diffraction (XRD) analysis confirmed the retention of the hexagonal wurtzite ZnO structure with a dominant (220) orientation. The ZnO phase became more pronounced at Ag concentrations above 1.5 wt%, while minor traces of cubic ZnO₂ appeared at higher doping levels. Scanning electron microscopy (SEM) revealed a uniform surface morphology with grain size variations influenced by Ag incorporation. Optical characterization showed high transmittance (~80%) in the 350–1200 nm range, accompanied by a gradual reduction in the optical bandgap from 3.75 eV to 3.5 eV as Ag content increased. Electrical measurements indicated enhanced conductivity, which peaked at 3 wt% Ag. The optimal balance between transparency and conductivity was achieved at 0.5 wt% Ag. These films demonstrated multifunctional potential in photocatalysis, biomedicine, and optoelectronics due to their improved crystallinity, surface area, and reactivity.

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This study investigates the effect of amine types on the structure of organosilica materials for CO₂ separation. The materials were synthesized using primary (3-amino propyl triethoxy silane (APTES)), secondary (bis-[3-(trimethoxysilyl) propyl] amine (BTPA)), and tertiary (tris (3-trimethoxysilyl propyl) amine (TTPA)) precursors, differing in linking units and alkoxy group numbers. These materials show high stability and improved CO₂ separation. Preliminary optimization was conducted on BTPA to determine the best type of acid catalyst, water-to-silane mole ratio, and catalyst-to-silane mole ratio. Material characterization was performed using FTIR, XRD, TGA, N_2, and CO₂ adsorption-desorption isotherms. The results revealed that a weak acid catalyst (acetic acid-HAc) produced a less stable Si-O-Si framework, while HNO₃ formed more ordered frameworks. A water-mole ratio of 50 was needed for complete hydrolysis of one alkoxy group; thus, ratios of 150, 300, and 450 were used for APTES (3-alkoxy), BTPA (6-alkoxy), and TTPA (9-alkoxy), respectively. Higher acid ratios accelerated the formation of well-ordered Si-O-Si frameworks. CO₂ capture evaluations showed that the secondary amine of BTPA exhibited the highest CO₂ adsorption due to enhanced interaction and carbamate formation, followed by APTES > TTPA. APTES showed better CO₂/N₂ separation at low pressures due to lower steric hindrance and smaller membrane pore size, which improves the adsorption ability and separation. The membrane performance is in agreement with material characterization, which shows CO₂ permeance of 2.1 (times) 10^-8mol m⁻² s⁻¹ Pa⁻¹ and the highest CO₂/N₂ separation of 17 for APTES. This study provides insights into optimizing amine-functionalized organosilica for efficient CO₂/N₂ separation. The optimized membranes show promising potential for efficient industrial CO₂/N₂ separation performance, offering competitive performance relative to commercially available membrane technology.