Journal of Sol-Gel Science and Technology最新文献

This work reports a detailed first-principles investigation of CaXmO₃ (Xm = Zr, Y, Rh) perovskite oxides using density functional theory (DFT) calculations implemented in the Wien2k. The study systematically examines the structural, electronic, optical, mechanical, and radiation attenuation characteristics of these materials to evaluate their potential for technological applications. Electronic band structure analysis reveals that CaZrO₃ exhibits a direct band gap of 4.1 eV, while CaYO₃ and CaRhO₃ show spin-polarized band gaps of 0.8/2.1 eV and 0.6/2.0 eV, respectively, suggesting possible applications in spin-based electronics. The presence of partially occupied d-states leads to high charge carrier concentrations approaching 10²¹ cm⁻³. Optical property calculations indicate moderate reflectivity in the visible range with enhanced UV reflectivity above 13 eV, making these materials promising for UV shielding applications. Mechanical property evaluation through elastic constant calculations confirms structural stability, while anisotropic sound velocity profiles suggest potential thermoelectric utility. Radiation shielding analysis demonstrates that CaRhO₃ exhibits superior gamma attenuation characteristics, particularly at lower energies, attributed to its higher effective atomic number compared to the other compounds. The comprehensive computational analysis presented in this study establishes CaXmO₃ perovskites as versatile functional materials with potential applications in optoelectronics, spintronics, and radiation protection technologies. These theoretical predictions provide valuable guidance for subsequent experimental studies and materials development efforts.

The fabrication of low cost and stable electrocatalysts for OER (oxygen evolution reaction) may be achieved by incorporating transition metal sulfides with conductive polymers, especially polyaniline. The present study investigates the hydrothermal synthesis of Ni₃S₂@PANI composite for OER activity. The composite material shows characteristics of a much greater surface area and an electrochemically active surface area (381 cm²). For electrocatalytic performance, material performed very well at 10 mA cm^–2 j (current density), showing a low η overpotential (230 mV) and Tafel slope (39 mV dec^–1) in basic medium (1.0 M KOH). The prepared sample exhibited remarkable long-term durability, maintaining its efficiency over 30 h of endurance testing and after 3000 cycles, with a minimal R_ct value (0.44 Ω), indicating superior cyclic durability and low impedance. Furthermore, the integration of PANI effectively enlarged surface area and enhanced the electrical conductivity of material, resulting in a marked advancement in its OER performance. These strategic modifications elevated Ni₃S₂@PANI electrocatalyst’s efficiency, rendering it as a strong candidate for advanced water-splitting technologies.

Energy storage and environmental pollution are currently two major problems facing the world. Supercapacitors are an innovative, sustainable energy storage technology with several practical and environmental benefits, like an extended lifespan, a greater power density and a low environmental impact. This research employed a hydrothermal method to fabricate a MnCo₂O₄/PANI (MCO/PANI) nanohybrid as a supercapacitor electrode material. The electrode material’s interface properties, patterns and morphology were analyzed using various analytical techniques. X-ray diffraction (XRD), scanning electron microscopy (SEM) and Brunner emitting teller (BET) analytical techniques used to assess, morphology, area and phase purity of manufactured electrode material. Electrochemical techniques like cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), electrochemical impedance spectroscopy (EIS), chronoamperometry (CA) and electrochemical surface area (ECSA) used to evaluate electrochemical quality of a manufactured electrode. MCO/PANI nanohybrid demonstrated a specific capacitance (C_s) of 1661.11 F/g at 1 A/g with specific power (S_P) of 265 W/kg and specific energy (S_E) of 64.80 Wh/kg. Additionally, the solution resistance value (R_s) of 0.88 Ω indicates that MCO/PANI nanohybrid material exhibits a low internal resistance. The composite material electrode exhibited exceptional stability in 3.0 M KOH over 3000^th cycles. Supercapacitor technology has entered a new era with improved stability, performance parameters and results demonstrate significant potential for application in future energy storage devices.

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This work reports a novel method for enhancing solar energy applications by synthesizing high-performance nanostructured PPy@AF hydrogel as photocatalyst under controlled conditions. The incorporation of acid fuchsin (AF) as a dopant into polypyrrole (PPy) imparts unique supramolecular properties to the hydrogels, enabling efficient chemical transformations, including C-H bond activation. The incorporation of AF as a dopant into PPy imparts unique supramolecular properties to the hydrogels, enabling efficient chemical transformations, including C-H bond activation. These dopant-enhanced hydrogel frameworks exhibit superior catalytic efficiency, offering a sustainable and eco-friendly solution for energy conversion processes. The study highlights the synergistic impact of dopant inclusion in enhancing the stability, selectivity, and reaction kinetics of the hydrogels. This innovation has the potential to contribute to the development of advanced materials in solar energy systems, where efficient catalytic reactions are essential. Overall, the findings support the advancement of high-performance, dopant-modified nanostructured hydrogels with promising applications in renewable energy and green chemistry.

Over the past few decades, the issue of toxic and reactive gases has been of concern for environmental safety and human health, which in turn has led to ongoing developments in gas detection technology. Spinel ferrites are well known as suitable candidates for gas sensing. This study examines Zn_xCu_0.2-xMn_0.8Fe₂O₄ (x = 0.0 to 0.2) nanoparticles, including their synthesis by sol-gel processing, characterization, and gas-sensing properties, as a sensor for nitrogen dioxide (NO₂). The formation of a cubic spinel structure was confirmed by X-ray diffraction analysis, with the crystallite size decreasing from 73 nm to 67 nm with increasing zinc content. Field emission scanning electron microscopy revealed a decrease in particle size with increasing Zn content, which contributed to increased surface area and porosity. The presence of distinct absorption bands in the Fourier transform infrared spectra at 597–613 cm⁻¹ and 389–401 cm⁻¹ was attributed to metal-oxygen vibrations in the spinel configuration. The gas response of Zn_xCu_0.2-xMn_0.8Fe₂O₄ nanoparticles exhibited improved sensitivity due to increased surface area as the crystallite size decreased, and the sensors exhibited a strong response towards NO₂ in gas sensing tests. The best performance was observed with Zn_0.2Mn_0.8Fe₂O₄, exhibiting higher sensitivity and shorter response time. These results suggest that Zn_xCu_0.2-xMn_0.8Fe₂O₄ ferrites are viable candidates for high-performance NO₂ gas sensors, with implications for understanding gas-sensing behavior associated with tuning composition and structural properties.

Organic-inorganic hybrid sol-gel coatings are effective and environmentally friendly alternatives to chromium(VI) pretreatment for aluminum alloys. The advantage of preparing coatings via the sol-gel method is that it allows obtaining coatings with optimized properties by varying synthesis parameters. In this work, a γ-GPS-ZrO₂ hybrid sol for surface pretreatment of AA2024-T3 was prepared by mixing pre-synthesized nano-zirconia (ZrO₂) sol into hydrolyzed γ-glycidyl etheroxypropyltrimethoxysilane (γ-GPS). Sol-gels with Si-Zr molar ratios of 2, 3, and 4 were applied to the aluminum alloy surface by coating and cured in an oven at 70 °C to form films. Electrochemical impedance spectroscopy (EIS) was used to evaluate the corrosion behavior of the sol-gel coatings on the aluminum alloy surface in 0.5 M NaCl solution. The morphology and chemical structure of the prepared hybrid coatings were analyzed by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Results show that increasing the Zr-Si molar ratio enhances the crosslinked inorganic network in the sols, leading to increased initial coating resistance and corrosion resistance. However, this also reduces the connectivity of the organic network, enhancing coating hydrophilicity and promoting water-induced degradation, which negatively impacts corrosion resistance. In this study, balancing these opposing trends (corrosion resistance vs. hydrophilicity) was achieved at a Si-Zr molar ratio of 3, yielding coatings with optimal comprehensive performance.

Water pollution from industrial effluents remains a major global challenge and demands effective and eco-friendly treatment plans. In this work, we report for the first time the integration of micro–nanobubble (MNB) technology with a ternary PbFe₁₂O₁₉/g-C₃N₄/rGO (PGR) nanocomposite for photocatalytic dye degradation and antibacterial applications. The PGR nanocomposite was synthesized via a hydrothermal process and systematically characterized by XRD, SEM, Raman and FTIR analyses. The band gap of pristine PbFe₁₂O₁₉ (2.94 eV) was successfully tuned in the composite (2.40 eV). The PGR nanocomposite achieved rapid degradation of methyl orange (95%) and crystal violet (98%) following pseudo-first-order kinetics with rate constants of 0.024 and 0.022 min⁻¹ respectively. The unique synergy between rGO-mediated charge transfer, g-C₃N₄ sensitization and MNB-induced reactive oxygen species generation led to enhanced electron mobility, suppressed recombination and superior catalytic efficiency. Moreover, the composite exhibited strong antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa. This study introduces a novel micro–nanobubble driven photocatalytic platform, offering a promising and sustainable route for wastewater purification coupled with antibacterial functionality.

This work targets a clear structure–property link in BaMn_0.5Ti_0.5O₃ (BMTO) by correlating sol–gel–derived crystal chemistry with temperature-dependent dielectric and electrical responses. Phase-pure rhombohedral perovskite (R3c) was confirmed by Rietveld refinement, with nanoscale crystallites (≈45–47 nm) and dense microstructure (≈124 nm grains) evidenced by XRD/SEM; EDS verified near-stoichiometric composition. Dielectric spectra (1 kHz–1 MHz, 200–320 K) show strong frequency dispersion, ε′ decreases with frequency but increase systematically with temperature, consistent with Maxwell–Wagner interfacial polarization and thermally activated hopping. AC conductivity follows Jonscher’s power law and rises with temperature, indicating small-polaron hopping and overall negative temperature coefficient of resistance behavior. Impedance and modulus analyses reveal non-Debye relaxation dominated by grain-boundary processes; Nyquist plots are well described by an R_s–(R_gb||CPE) equivalent circuit, with grain-boundary resistance falling from ~255 Ω (200 K) to ~55 Ω (320 K) and the relaxation frequency shifting from ~3 kHz to ~30 kHz as temperature increases, while the CPE exponent approaches unity (0.86 → 0.93), indicating more ideal capacitive behavior at higher temperatures. These results show that B-site Mn/Ti substitution and associated defect chemistry (octahedral tilts, oxygen-vacancy assisted hopping) govern polarization and transport. BMTO therefore offers thermally tunable dielectric response and semiconducting conduction desirable for capacitors, sensors, and other multifunctional electronic components.

In the last decades, alkoxide sol-gel chemistry provided an exceptional tool for the synthesis of nanostructured building blocks and designing application of novel materials. To keep up with the latest advancements in this field, a group of Argentine researchers established the Buenos Aires School of Materials Synthesis and Sol-Gel Processes, which has been held every 2 years at Buenos Aires—Argentina, since 2003. The course, aimed at young graduate students, postdoctoral researchers, and industry professionals, focuses on both the fundamentals and the newest developments of sol-gel processes. Also, during 40 h of laboratory-based work, they become immersed in the typical techniques and skills in sol-gel synthesis and materials characterization. These “hands-on” experimental sessions are the defining feature of this school as they explore key sol-gel related processes: hydrolysis and condensation kinetics, wet-lab synthetic approaches, and materials characterization techniques. In the work presented here, the students employ the well-known Stöber´s method for obtaining SiO₂ colloidal particles. Tetraethoxysilane hydrolysis and condensation kinetics are followed using a conductometer, and the time-dependent data obtained are interpreted using a simple consecutive reaction kinetics mechanism. Later, the students explore simple one-pot post-grafting colloidal surface chemical modifications, which are confirmed through infrared spectrometry and zeta-potential measurements. Carefully controlled additions of the alkoxide precursor allow for experimentation on increasing particle diameter, which can be readily confirmed using scanning electron microscopy. Moreover, encapsulation within the SiO₂ framework with cationic luminescent dyes as [Ru(bpy)₃]²⁺ results in photochemical hybrid platforms. In essence, this laboratory activity encompasses several sol-gel and colloidal chemistry concepts suited for an advanced chemical course on materials synthesis.