Journal of Sol-Gel Science and Technology最新文献

Silicic acid solution, which is prepared from water glass followed by extraction with tetrahydrofuran (THF), is focused on an environmentally friendly and inexpensive source of silica. In this study, we aimed the preparation of bulk porous silica with low environmental impact and cost, and desulfurization of its supported ZnO was investigated. Bulk porous silica was prepared by the condensation of silicic acid/THF in the presence of Pluronic P123. Suitable condition was investigated for the formation of crack-free bulk body with high surface area and reproducibility under the molar ratio of H₂O/Si and Si/Pluronic P123 on 121 and 100, respectively. From nitrogen adsorption–desorption measurements, this bulk porous silica was categorized into micro–mesoporous silica. Moreover, Pluronic P123 was extracted and recycled. Bulk porous silica-supported 15 wt% ZnO was prepared by the impregnation of ZnCl₂ followed by calcination in air. The desulfurization ability was 8.7 mg/g.

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Zirconia has become widely used in dentistry due to its mechanical strength, biocompatibility, and esthetics. However, durable resin bonding to zirconia remains a challenge due to its inert surface chemistry. This study demonstrates an approach for tribochemical silica coating of zirconia using a silica-coated zirconia powder synthesized via sol-gel chemistry from upcycled zirconia milling waste. Systematic variation of blasting pressures and durations revealed an optimized protocol of 0.28 MPa for 10 s, achieving an exceptional resin bond strength of 39.13 MPa. Extensive materials characterization, including field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), and X-ray diffraction (XRD) elucidated the interfacial mechanisms governing adhesive performance. These techniques confirmed the uniform deposition of a nano-silica layer through mechanical embedding and heating upon particle impact. This silicatization transformed the intrinsic hydrophobicity and created reactive hydroxyl groups for subsequent silanization. Precisely controlled roughening was evidenced by atomic force microscopy, with a root mean square roughness of 676 nm for optimal coatings. X-ray diffraction confirmed silica incorporation generated some transformation from the metastable tetragonal to the monoclinic phase, however less than for an analogous commercial alumina-based powder. Realization of stronger, imperceptible ceramic modification introduces possibilities for thinner, aesthetically superior restorations. This demonstration of upcycling zirconia waste into tunable surface coatings represents a paradigm shift in sustainable materials design and unprecedented value creation from disposal debris. Insights gained can inspire scalable, broadly applicable surface engineering solutions utilizing waste streams.

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The variation of calcium phosphate formation rate on calcium titanate surfaces synthesized via sol-gel (CTSol) and solid-state reaction (CTS-S) at 600 °C for 10 h, were investigated using DSC, FTIR, XRD, DLS-Zeta potential, FESEM-EDS, BET, and ICP-OES, focusing on the relationship between surface morphology and calcium phosphate formation ability. Both powders had meso-porosities with a mean pore diameter of 45 and 54 nm, respectively. While CTSol particles had a diameter of about 100–250 nm, CTS-S had nanosized particles (35–40 nm) with the configuration of parent P25 TiO₂. CTS-S had a higher specific surface area (26.14 m². g⁻¹), pore volume (0.36 cm³.g⁻¹), and pore size (D = 54.51 nm) than CTSol (11.09 m². g⁻¹, 0.12 cm³.g⁻¹, D = 44.97 nm). By submerging disk-shaped samples in SBF solution, their bioactivity was evaluated for up to 14 days. Both samples formed calcium phosphate at similar rates. Despite having a smaller surface area, CTSol makes up for it with a higher rate of Ca²⁺ dissolution. Whereas the calcium phosphate initial particles on the surface of CTS-S were spherical, the needle-like features on the surface of CTSol were created by immersion in SBF.

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Tantalum Oxynitride (TaON) has been recognized as a visible-light photocatalyst, and is thus expected to be applicable to semiconductive and transparent conductive film. In this study, TaON thin films were prepared on a silica glass substrate by nitridation of Ta₂O₅ precursor films using urea. The precursor Ta₂O₅ films were prepared from Ta(OC₂H₅)₅. Then, urea and the precursor Ta₂O₅ thin film were placed at the upstream and downstream sides in a tube furnace, respectively, and heated under a nitrogen flow to supply the vaporized urea constituent to the surface of the Ta₂O₅ precursor film. Thin film of β-TaON was obtained by a heat treatment at 1000 °C with urea under nitrogen flow. The transmittance of the film was 70 ~ 80% in the wavelength region from 500 to 800 nm, and the optical bandgap of the film was 2.65 eV.

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The UV polymerization method is an efficient method to fabricate zinc oxide (ZnO) thin films. So far, this method is mainly based on the self-polymerization of zinc-based monomers, followed by annealing. However, the self-polymerization usually leads to long polymerization times, irregular morphologies of the product, and reaction wastes. To address these issues, the novel fabrication process and recipe to form ZnO films are proposed. This proposal uses zinc-based monomers and their solvent (acrylic acid) collectively as reactants in the polymerization process. The cross-linking between them significantly reduces the polymerization time to a few seconds without the reaction waste, and leads to a well-defined surface morphology of the zinc-based precursor film. The structures, morphologies and optoelectric properties of the ZnO films annealed at different temperatures are characterized. The results show that the ZnO nanocrystals exhibit a hexagonal wurtzite crystal structure. The ZnO films exhibit an average transmittance as high as 98% in the visible spectrum, and the optical bandgaps of 3.24–3.29 eV. The electrical performance of the film is strongly correlated with the oxygen vacancies content, leading to the highest carrier concentration and the lowest electrical resistivity of 4.09 × 10⁻¹ Ωcm at the annealing temperature of 450 °C.

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This study explores the comprehensive characterization of Y³⁺ and Co²⁺ co-substituted LaFeO₃ nanoparticles synthesized via the sol-gel auto-combustion method. The synthesized samples, La_1-xY_xFe_1-y Co_yO₃ (x = 0,0.10 and y = 0,0.03,0.05,0.07) were characterized by employing various techniques such as x-ray diffraction (XRD), Scanning Electron Microscopy (SEM) with EDX, Raman spectroscopy, UV-visible spectroscopy, and Vibrating Sample Magnetometry (VSM). The Raman and XRD analysis, supported by Rietveld refinement, provided conclusive evidence of a pure orthorhombic LaFeO₃ phase. Microstructural studies unveiled an agglomerate-type, irregular particle distribution, while EDX analysis confirmed the elemental composition. The XPS study gives evidence about the presence of both Fe²⁺ and Fe³⁺ oxidation states, and Co has a Co³⁺ oxidation state. UV-vis spectroscopy demonstrated enhanced visible light absorption, revealing a reduced bandgap with increasing doping percentages. VSM measurements exhibited M-H loops, substantiating the weak ferromagnetic nature of the materials. Moreover, these nanoparticles exhibit dielectric constants and low dielectric losses, making them suitable for use in devices for communication. Overall, these findings may offer valuable contributions to the understanding of nanomaterial characteristics for potential applications in diverse fields.

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Conventional antireflective films for solar cells are usually porous for high transmittance, but still suffer from weak weatherability and poor hydrophobicity because water droplets can enter porous films easily and degrade the antireflection performance. In order to achieve a good balance between high transmittance and excellent hydrophobicity, superhydrophobic porous SiO₂ bilayer film with refractive index gradient was designed. Mesoporous SiO₂ film with high refractive index as inner layer was synthesized on the glass at first and then superhydrophobic porous SiO₂ film with low refractive index was prepared by a facile sol-gel method using hexamethyldisilane (HMDS) as modifier. As HMDS content increases, the hydrophobicity of the upper layer was significantly improved while the transmittance was slightly decreased because the -OH on the layer were gradually replaced by -CH₃. When volume ratio of HMDS to Alkali (V_HMDS/Alkali) was 0.6, a large water contact angle (WCA) of 163.6° and high transmittance increase of 2.82% was obtained. When applying this film to the glass on the surface of perovskite solar cells, an obvious increase (0.78%) in photoelectric conversion efficiency (PCE) was obtained. Especially, the superhydrophobic SiO₂ bilayer film exhibited a higher transmittance increase of 3.19% in the broad wavelength range of 380–1100 nm and larger WCA of 161°. In addition, after a 24-h immersion in a water bath at 80 °C, the transmittance was only reduced by 0.26%, indicating a good weatherability. Therefore, this work can provide a more innovative, superior, and facile method to prepare promising antireflection coatings for solar cells.

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Presently, the utilization of nanomaterials has evolved as an appealing alternative for ever-changing healthcare obstacles due to their distinctive features and multifunctional applications. This work aimed to fabricate and analyze novel NiO/Ni₂O₃ nanoparticles (NPs) using Sargassum tentorium extracts and investigate their antioxidant and anticancer potentials. Diverse analytical instrumental tools were applied to explore NiO/Ni₂O₃ NPs, including UV–vis diffuse reflectance spectroscopy (UVDRS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution scanning electron microscopy (HRTEM), and energy-dispersive X-ray (EDX) analyses. HRTEM images revealed mostly quasi-spherical and wire-shaped NPs with average 97 and 87 nm sizes for NiO/Ni₂O₃ NPs. Afterward, the biological properties of the biologically manufactured NiO/Ni₂O₃ NPs were explored. This work assessed the anticancer potential of as-fabricated NiO/Ni₂O₃ NPs utilizing the MTT assay. The experiment assessed cell viability at doses ranging from 7.81 to 500 µg/mL during a 24 h period for the breast cancer cell line (MCF-7). The study outcomes demonstrate a concentration-dependent effect of fabricated NiO/Ni₂O₃ NPs on MCF-7 cells. The inhibition of MCF-7 cells increases with the concentration of NiO/Ni₂O₃ NPs, achieving an IC₅₀ value of 883.4 µg/mL in 24 h. Furthermore, the antioxidant potency of NiO/Ni₂O₃ NPs was examined via a free radical scavenging ABTS and DPPH assay. At a concentration of 50 μg/mL, NiO/Ni₂O₃ NPs also exhibited 74.71% ABTS scavenging and 71.62% DPPH scavenging inhibition, respectively. In conclusion, NiO/Ni₂O₃ NPs manufactured via Sargassum tenerrimum extracts could be promising candidates for further biomedical applications.

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This study successfully synthesized Fe₂O₃@rGO nanocrystals using a straightforward sol-gel method in a pigskin-gel (gelatin type A) environment. The fabricated nanocomposites include Fe₂O₃-linked nanosheets in a reduced graphene oxide-like double tetrahedral pyramid (DTP) structure and Fe₂O₃ nanocrystals resembling Cheetos puffs (CPs). The Fe₂O₃@rGO material was characterized through a variety of analytical techniques, including X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, elemental mapping, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, Raman spectroscopy, vibrating sample magnetometer, nitrogen physisorption, and electrochemical impedance spectroscopy. The photocatalytic efficiency of Fe₂O₃ and Fe₂O₃@rGO samples in demineralizing rhodamine B in an aqueous solution was thoroughly evaluated. Remarkably, the Fe₂O₃@rGO composites exhibited significantly enhanced photocatalytic activity and degradation efficiency compared to pure Fe₂O₃ nanocrystals. The improved performance can be attributed to effective electron transport between the reduced graphene oxide and the semiconductors, effectively reducing electron-hole recombination. Additionally, the Fe₂O₃@rGO nanocrystals demonstrated excellent magnetic properties, enabling easy separation and recovery after five cycles of reusability testing. These findings highlight the promising potential of this magnetic nano photocatalyst for efficient and sustainable wastewater treatment applications, particularly in the degradation of rhodamine B.

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The synthesis of titanium and lithium phosphates was studied using the sol-gel method. Particular attention was paid to phosphate precursors, which were mixtures of phosphate mono- and diesters prepared by solvolysis of P₄O₁₀ in isopropanol. The reaction of these precursors with titanium and lithium alkoxides yielded homogeneous gels and after drying and thermal cleavage of the esters at 300 °C, amorphous inorganic products. For the composition corresponding to the stoichiometric formula of a stable compound such as LiTi₂(PO₄)₃, the phase crystallized as early as 550 °C by nucleation from the amorphous mixture. Ionic conductivity measured at room temperature was of the order of 10⁻⁵ S·cm⁻¹ which increased after heat treatment at higher temperatures. If the composition did not correspond to a stable thermodynamic phase, phase separation occurred, and ionic conductivity decreased between 500 °C and 700 °C.

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