Journal of Sol-Gel Science and Technology最新文献

The current research explores the sustainable synthesis of AgNPs using 3,6-dihydroxyflavone, a bioactive flavonoid, and evaluates their multifunctional biological applications. The green-synthesized AgNPs were confirmed using UV-Vis spectroscopy, FTIR, XRD, SEM, TEM, EDS, DLS, and zeta potential analysis, confirming their crystalline nature, spherical morphology (22–28 nm), and moderate colloidal stability. The larvicidal potential of the AgNPs was assessed against An. stephensi, Cx. quinquefasciatus, and Ae. aegypti, with significant mortality observed at low concentrations, and LC₅₀ values ranging from 9.10 to 12.62 µg/mL. Histological examination revealed severe midgut damage in treated larvae, indicating disruption of digestive and structural integrity. The AgNPs also exhibited strong antioxidant activity in DPPH and ABTS assays. Significant antibacterial activity was observed against both Gram-positive and Gram-negative test pathogens, and the compounds potentially inhibit biofilm formation. Furthermore, cytotoxicity studies demonstrated dose-dependent anticancer activity against MCF-7 cells while screening for minimal toxicity in normal Vero cells. The ecotoxicological assessment using Artemia salina confirmed that the AgNPs were safe to non-target aquatic organisms at effective larvicidal doses. In parallel, molecular docking showed strong affinity for 1MV8 (-7.35 kcal/mol, Ki 4.12 µM), supporting its role in the antibacterial, anti-biofilm, and anticancer effects of the synthesized AgNPs. Overall, this study highlights the potential of 3,6-dihydroxyflavone-mediated AgNPs as a promising green nanoplatform for mosquito control and biomedical applications.

Graphical Abstract

Bioactive acrylic bone cements were created through the use of alendronate sodium functionalized poly(methyl methacrylate-co-acrylic acid) reinforced with calcium titanate or bioglass 45S5. Calcium titanate (CT) with an average diameter of 86 nm were synthesized via the sol-gel method. Bioglass was also synthesized by the sol-gel method without nitrate precursors and thermally treated at 380 (BG380) and 700 °C (BG700). BG380 showed crystalline rhenanite along with amorphous silicates, whereas BG700 contained fully crystalline combeite-like and needle-shaped silico-rhenanite (∼125 nm diameter). The copolymer includes spherical particles (∼398 nm) with a zeta potential of −51 mV. Alendronate resulted in calcium phosphate formation in crack zones after 7 days, while the incorporation of bioglasses exhibited lower bioactivity because of their partial crystallinity. Contrary, CT led to enhanced deposition at crack openings within 3 days and complete closure of cracks (<16µm) after 14 days. CT-containing composite showed a compressive strength of 24 MPa prior to soaking in SBF, which dropped to 19 MPa afterwards. In comparison to similar studies, this does not eliminate the possibility of diminished crack healing as a result of calcium phosphate deposition. These results demonstrate that alendronate-functionalized copolymer matrices reinforced with bioactive ceramics can support localized calcium phosphate formation, particularly in crack zones.

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Multilayer ZnTiO₃ thin films were synthesized on porous silicon (PS) substrates via a sol–gel spin-coating process, and their structural, optical, and photocatalytic properties were systematically investigated as a function of layer number. X-ray diffraction and Raman spectroscopy confirmed the formation of the hexagonal ZnTiO₃ phase, with enhanced crystallinity and reduced microstrain in thicker films. UV–Vis spectroscopy revealed a red shift of the absorption edge and a corresponding decrease in band gap energy from 3.81 to 3.06 eV, attributed to improved light harvesting and defect-mediated transitions. Morphological analyses indicated a transformation from discontinuous nanoparticles to compact nanocrystalline films with higher surface coverage on PS. These structural and optical improvements led to superior photocatalytic activity, achieving nearly complete methylene blue degradation under sunlight within 180 min. The results demonstrate that the synergistic coupling between ZnTiO₃ and porous silicon, combined with multilayer stacking, effectively enhances light absorption and charge separation, making this heterostructure a promising candidate for efficient solar-driven photocatalysis and environmental remediation.

Alkaline water electrolysis is a well-known process with a lot of promise for producing renewable energy, but it needs the right catalyst. The effectiveness of water electrolysis can be greatly improved with the right electrocatalyst. In order to catalyse the oxygen evolution reaction (OER), a multifunctional electrocatalyst made of aluminum sulfide–anchored graphene oxide (Al₂S₃/GO) was created using a hydrothermal process. The produced catalyst’s varied morphology and good crystallinity were validated by the physical characterization performed using XRD and SEM. In 1 M KOH, electrochemical performance was assessed using three-electrode system. The Al₂S₃/GO nanocomposite demonstrated a small Tafel slope of 35.4 mV dec⁻¹, a low overpotential of 218 mV at 10 mA cm⁻², and steady operating at elevated current densities up to 50 mA cm⁻². Additionally, after 5000 CV cycles, it maintained 92% of its starting current. The Al₂S₃/GO catalyst is stable, economical, and useful option for OER in alkaline solution, according to the overall results.

Despite the rising need for advanced antimicrobial materials to fight drug-resistant pathogens, conventional antibacterial treatments frequently have limited efficacy and stability issues. This study aims to overcome these issues by creating a unique Ag@ZIF-67 heterostructure that synergistically combines the structural benefits of metal-organic frameworks with the antimicrobial qualities of silver nanoparticles and provides longer-lasting and improved antibacterial activity. The heterostructure was created using a simple two-step procedure that involved in situ deposition of silver nanoparticles (Ag NPs) and controlled growth of zeolitic imidazolate framework-67 (ZIF-67). Scanning electron microscopy (SEM) confirmed the successful formation of the Ag@ZIF-67 heterostructure with well-dispersed Ag NPs (average size 10.96 nm) throughout the ZIF-67 matrix. The key innovation is the synergistic heterostructure design, which overcomes the rapid depletion and aggregation issues of traditional silver-based antimicrobials by allowing regulated silver release while producing reactive oxygen species through cobalt centers. Antimicrobial activity testing of Ag@ZIF-67 against common pathogens, including Staphylococcus aureus (S. aureus) and Klebsiella pneumoniae (K. pneumoniae), revealed superior inhibition compared to pristine ZIF-67 and Ag NPs, with minimum inhibitory concentrations (MICs) ranging from 3.9 to 7.8 μg/mL. This innovative Ag@ZIF-67 heterostructure represents a promising platform for preparing antimicrobial materials for healthcare and environmental applications.

Graphical Abstract

To enable efficient phenol red (PR) sensing over a wide pH range (1–12), copper oxide nanoparticle (CNPs) decorated anatase-silica (CAS) nanocomposite and gold nanoparticle (AuNPs) decorated anatase-silica (AAS) nanocomposite were synthesized by a sol–gel method at 80 °C. The AAS nanocomposite possessed a higher surface area ~251 m²/g and smaller crystallite size ~4 nm compared to the CAS nanocomposite surface area ~215 m²/g and crystallite size ~10 nm. In sensing analysis, PR encapsulated AAS (PR-AAS) exhibited a larger pKa around 10.8 and color response time (Ta) ~0.2 s at pH 12 than PR encapsulated CAS (PR-CAS). These results suggest PR-AAS nano composite sol is an excellent nanocomposite for swift and reliable pH sensing in environmental and food monitoring.

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In this study, an effective approach has been proposed for the single-stage preparation of fine powders of а Ni-Co alloy by application of the solution combustion synthesis (SCS) method, based on heating an aqueous solution containing metal nitrates and organic reducers, urea, and glycine. It has been established that only a combination of the selected reducing compounds, can led to a virtually single-phase nickel-cobalt alloy. Scanning electron microscopy, powder X-ray diffraction, EDS and XPS analyses were used to characterize the obtained material. Application of these methods allowed to reveal that trace amounts of the two main impurities, carbon and nitrogen, are distributed homogeneously in the alloy as a result of decomposition of the used reducers, and oxygen is present basically on the surface of the alloy in the form of physically and chemically absorbed molecules of water, metal hydroxide, or oxide. Using differential scanning calorimetry in combination with the thermogravimetric analysis, possible mechanisms of chemical transformations during the SCS process yielding the target Ni-Co alloy were discussed. The role of individual organic reducers at different stages of SCS was assessed.

Graphical Abstract

Visualized solution combustion synthesis process, SEM image of the obtained alloy, XRD pattern of the alloy, and DSC-TGA study of alloy formation.

Calcium aluminate with the mayenite structure (Ca₁₂Al₁₄O₃₃) is of significant interest for use as a catalyst support due to the ability of stabilizing such active particles as O^–, O₂^– or free electrons in the anionic sublattice. We explored the effect of toluene addition on the phase composition and pore structure of aerogels and xerogels with the mayenite stoichiometry with the goal of preparing nanocrystalline mayenite samples with high purity and high surface area. The addition of a two-fold toluene excess relative to alcohol with a five-fold water excess was found to yield samples with predominating mayenite phase and specific surface area ca. 110 m²/g after drying either over a hotplate in the air or in an autoclave followed by calcination in air at 500 °C. Meanwhile, calcium carbonate was the main crystalline phase if the process was carried out in the absence of toluene. The aerogel sample demonstrated excellent thermal stability. After calcination at 900 °C for 6 h it had the surface area of 48 m²/g and 93% of the mayenite phase.

Graphical Abstract

Toluene addition is shown to be a key factor for the formation of nanocrystalline mayenite (C12A7) phase in the aerogel and xerogel samples after calcination at 500 °C.