Journal of Sol-Gel Science and Technology最新文献

This study presents a sustainable synthesis of copper oxide (CuO) nanoparticles via a sol-gel approach utilizing prodigiosin pigment extracted from Serratia rubidaea as a green biogenic agent. To the best of our knowledge, this is the first report of employing prodigiosin from Serratia rubidaea in the sol-gel synthesis of CuO nanoparticles. Copper sulfate pentahydrate (CuSO₄·5H₂O) served as the precursor, reacting with the bio-pigment under controlled conditions to yield CuO nanomaterials. Comprehensive physicochemical characterization confirmed nanoparticle formation and composition: scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed morphology, Fourier-transform infrared (FTIR) spectroscopy identified characteristic Cu-O vibrational modes, energy-dispersive X-ray spectroscopy (EDAX) established the presence and proportions of copper, oxygen, and carbon, while X-ray diffraction (XRD) confirmed the monoclinic phase (JCPDS Card No. 00-001-1117). Ultraviolet–visible (UV–Vis) spectroscopy exhibited absorption peaks at 329.5, 365.0, and 388.5 nm, corresponding to an estimated optical band gap of 2.95 eV. The dual role of prodigiosin as a natural reducing and capping agent highlights the eco-friendly and innovative nature of this synthesis. The resultant CuO nanoparticles exhibit properties comparable or superior to those synthesised with other biological agents reported recently. Preliminary cytotoxicity assessment using the Sulforhodamine B (SRB) assay against MCF-7 breast cancer cells demonstrated a dose-dependent reduction in cell viability, achieving a maximum mortality of 32.9% at 80 μg/mL. Although the half-maximal inhibitory concentration (IC₅₀) was not reached within the tested range, these findings suggest promising anticancer potential and warrant further biomedical investigations of the synthesised biofunctionalized CuO nanoparticles.

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Silica-based materials can stimulate bone regeneration; however, pure silica materials have shown some disadvantages, such as low degradability and brittleness, which can be overcome by developing hybrid materials. For bone tissue engineering, the organic co-network should contain adhesion sequences to enhance cell adhesion, be bound to the silica network and in lower proportion than silica. With this purpose, the tetraethyl orthosilicate (TEOS) sol-gel reaction was used to create hybrid ink for 3D printing with gelatin as polymer, and 3-glycidyloxypropyl(trimethoxysilane) (GPTMS) as cross-linking agent. By adjusting the TEOS, GPTMS and gelatin proportions, four different hybrid inks were obtained with a wide variety of physicochemical properties and all demonstrating a high printability and shape fidelity. As result of this silica-gelatin hybrids, scaffolds had faster degradation rate, higher water uptake and improved mechanical properties, when compared to the pure silica scaffolds. All these properties were achieved without losing any apatite formation capacity due to gelatin presence, and improving initial cell adhesion and proliferation in two of the developed inks. The silica-gelatin hybrid inks showed promise in the development of tailored 3D printed scaffolds.

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Controlling the optical and structural properties of metal-organic frameworks (MOFs), which have emerged as highly promising materials for a variety of applications in recent decades, is a challenging task that may increase their application possibilities. Thus, we examined the impact of thermal annealing at temperatures between 100 °C and 400 °C, along with silver (Ag) and silver nanoparticle (AgNP) doping, on the optical and structural characteristics of MOF thin films. For this aim, we prepared 2,5-pyridinedicarboxylate-containing metal-organic framework (UiO-66-PDC) and converted it to Ag⁺ (UiO-66-PDC-Ag) and AgNP (UiO-66-PDC-AgNP) containing MOFs. Afterwards, we prepared thin films of these MOFs using the spin coating technique. The SEM images showed a decrease in the grain sizes of UiO-66-PDC thin film and a disruption of the uniform structure with increasing annealing temperature. The average reflection values of UiO-66-PDC thin films decreased from 31.58% (at 100 °C) to 23.85% (at 400 °C). In addition, the band gap values calculated by the Tauc method are 2.85 eV, 2.77 eV, 2.62 eV, and 2.58 eV at 100 °C, 200 °C, 300 °C, and 400 °C for UiO-66-PDC, respectively. The band gap values at 100 °C were determined as 2.62 eV for the UiO-66-PDC-Ag film and 2.05 eV for the UiO-66-PDC-AgNP film. Consequently, Ag and AgNP dopants had an adverse effect on the optical properties of MOF thin films. However, lower band gaps were observed, which is crucial for catalytic processes.

Industrial development faces severe pollution challenges, particularly in treating refractory dyeing wastewater. Photocatalytic technology offers a promising solution due to its stability, efficiency, and environmental benefits. Compared to traditional biochemical methods, nano-TiO₂ enables more complete organic degradation. This study synthesized La-N co-doped TiO₂ (La-N/TiO₂) and multi-walled carbon nanotube-supported composites (La-N/TiO₂/MWCNTs) via sol-gel processing. X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), photoluminescence (PL) spectra and Brunauer-Emmett-Teller (BET) characterization confirmed anatase phase retention in all doped catalysts. Co-doping reduced TiO₂ crystallite size and induced a 2.64 eV bandgap red shift. Critically, XPS analysis confirmed atomic-scale bonding via distinct binding energies: N 1 s at 399.6 eV (O-Ti-N) and O 1 s at 529.8 eV (Ti-O-La), verifying dopant lattice incorporation. MWCNT incorporation enhanced specific surface area and formed composite encapsulation. Under optimized conditions (xenon lamp, 180 min; calcination 500 °C, 3 h; 1.5%La-3%N; 15 cm light intensity; pH 8; 0.8 g/L dosage; 25 °C), La-N/TiO₂ achieved 66.73% RhB degradation and 62.80% COD removal. The La-N/TiO₂/MWCNTs adsorption-photocatalysis synergy significantly outperformed this, attaining 98.53% RhB removal and 87.80% COD reduction within 180 min. Systematic scavenger experiments confirmed that hydroxyl radicals (·OH) and superoxide anions (·O₂^-) serve as the dominant active species in the degradation process, with contributions significantly exceeding those of direct photogenerated hole (h⁺) and electron (e^-) oxidation. Degradation product analysis identified a pathway involving sequential N-deethylation/decarboxylation, chromophore cleavage, and aromatic ring opening, culminating in complete mineralization. Multidimensional toxicity assessment confirmed progressive detoxification, with final intermediates showing “Not Harmful” acute toxicity, reduced developmental toxicity, and no mutagenicity. This work provides new insights into practical applications of adsorption-coupled photocatalysis for RhB elimination.

A comparative study on the effect of thickness in the photocatalytic decoloration of methylene blue (MB) dissolved in water was conducted using three semiconductor oxides: zinc oxide (ZnO), tin oxide (SnO₂), and titanium dioxide (TiO₂). These oxides were used in the form of thin films with varying thicknesses of approximately 100, 200, and 300 nm. All films were deposited using the cost-effective dip-coating technique at a moderate processing temperature of 400 °C on inexpensive glass substrates with sol–gel solutions. The structural, morphological, and compositional properties of the films were analyzed using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Raman spectroscopy, respectively. The degradation of MB was studied by varying the thickness and using three different types of semiconductor oxides through measurements of the optical absorbance of the decolorized liquid by the photocatalytic process. Structural analysis showed that ZnO and SnO₂ films were polycrystalline with preferential growth of (002) and (110) planes, respectively, whereas an amorphous structure was observed for TiO₂ films. Additionally, morphological properties confirmed that the surfaces of all films were composed of nano-grains in round and irregular shapes. Based on all the results reported in this work, it is apparent that the authors believe the degradation efficiency of MB depends on the crystal structure and morphological surface, which in turn depends on the thickness of the film and the type of semiconductor material used as a catalyst. The highest degradation efficiencies, tested with UV–vis radiation for 120 min and an initial concentration of 10 mg/L, were 100, 88, and 76% for ZnO, SnO₂, and TiO₂ films, respectively. These degradation efficiencies were observed in the films with the greatest thicknesses. It was found that as the thickness of the deposited films increases, their physical properties improve, which in turn enhances their efficiency in MB degradation.

This research presents an in depth study of the electrical and antibacterial activity of Co_xCu_1-xFe₂O₄ and their polymer nanocomposites. The citrate precursor auto-combustion method was successfully used to synthesize the nanostructured Co_xCu_1-xFe₂O₄. To investigate the impact of PEG on the physical characteristics, polymer-blended ferrite nanoparticles were produced using PEG-4000 as a capping agent. X-ray diffraction analysis of Co_xCu_1-xFe₂O₄ verified their cubic spinel structure, and Rietveld analysis was used to further refine the results using FULLPROF software. The lattice constant (a) increases, while the crystal size decreases by increasing Co²⁺ concentration. According to the measured elastic properties, PEG in PEG/Co_xCu_1-xFe₂O₄ nanocomposites made it softer and more durable. CuFe₂O₄ was found to have maximum conductivity and dielectric loss but lower dielectric permittivity. PEG enhances the dielectric permittivity of some Co_xCu_1-xFe₂O₄. The Nyquist plots were fitted by the ZSimpWin program, and the equivalent circuit demonstrates that the electrode, grain, and grain boundaries contributed to the polarization process. Co_xCu_1-xFe₂O₄ samples are suitable for high-frequency applications due to their low dielectric loss. Thermal conductivity tests reveal that CuFe₂O₄ has the highest value among the ferrite samples. The thermal conductivity of the composites exceeds that of pure ferrites. The nanoparticles and their composites exhibited antimicrobial activity against both gram-negative bacteria (E. coli) and gram-positive bacteria (Staph. Aureus). These intriguing findings suggest that these materials are excellent candidates for technological and therapeutic applications.

Reduced graphene oxide supported Y₂TiO₅ nanocomposite was synthesized via the sol-gel method and subsequently employed as a photocatalyst. Its crystal structure morphology, chemical composition, and optical properties were studied using XRD, FT-IR, SEM with EDAX, UV-DRS, TEM, BET, and XPS spectroscopy. The crystallite dimensions were determined using Scherer’s formula resulting in values of 26, 36, 47 and 69, nm respectively, for rGO, TiO₂, Y₂TiO_5, and rGO/Y₂TiO₅. The rGO exhibited a sheet-like structure, while in the rGO/Y₂TiO₅, Y₂TiO₅ was distributed over the surface of the rGO.The band gap values calculated from UV –DRS analysis were found to be 3.38, 2.17, 2.77 and 1.99 eV for rGO, TiO₂, Y₂TiO_5, and rGO/Y₂TiO₅, respectively. The photoactivity of the materials was investigated using methylene blue (MB) dye degradation in the presence of solar radiation. The findings revealed that under exposure to sunlight and UV light, the TiO₂, Y₂TiO_5, and rGO/Y₂TiO₅ photocatalysts resulted in the decomposition of up to 65, 85, 98 and 61, 75, 91% respectively, of the MB initially present. These results indicate that the synthesized materials have good photocatalytic and antibacterial activities, with potential applications in environmental remediation.

Harmful metal ions and persistent organic pollutants in textile wastewater create a significant environmental problem. This study explore the photocatalytic activity of Sol-Gel synthesized CuFeS₂ composites doped with varying concentrations of Zn (1, 5, and 10 mol%) for the degradation of harmful Cr(VI) ions under visible light irradiation. XRD results showed that CuFeS₂@Zn 10 mol% composites exhibited a smaller crystallite size (11 nm) than the pure CuFeS₂ sample (23 nm) and FTIR analysis indicates Zn²⁺ incorporation into the CuFeS₂ structure. FESEM analysis shows a transition from a platelet to an amorphous morphology upon Zn doping. Band gap energy decreased from 2.41 eV to 2.09 eV for CuFeS₂@Zn 10 mol% composites. XPS peak shifts in Cu 2p, Fe 2p, and S 2p spectra after Zn doping indicate successful incorporation of Zn into the CuFeS₂ structure. BET analysis revealed an increase in surface area from 49 m²/g for pure CuFeS₂ to 139 m²/g for CuFeS₂@Zn 10 mol%.The CuFeS₂@Zn 10 mol% catalyst facilitated the reduction of Cr₂O₇²⁻ to Cr³⁺ within 100 min with a rate constant of 3.041 min⁻¹. 6 mg of CuFeS₂@Zn 10 mol% catalyst (prepared at pH 6) degraded Cr(VI) completely within 60 min. The Zn doped CuFeS₂ catalysts generated a greater number of h⁺ and e⁻, promoting Cr(VI) reduction through enhanced light absorption, improved charge separation, and greater redox capability. This study offers important findings for the design and development of highly efficient photocatalysts for toxic metal ion wastewater remediation.