Journal of Sol-Gel Science and Technology最新文献

In this paper wepresent the investigation of the luminescence, photocatalytic, magnetic, and structural properties of Eu_1-xBi_xFe_1-yMn_yO₃ (0 ≤ x ≤ 0.8, 0 ≤ y ≤ 0.4) polycrystalline nanoparticles synthesized via the sol–gel method. Rietveld refinement of the room temperature (RT) powder X-ray diffraction pattern confirmed the presence of an orthorhombic crystal structure with the Pnma space group. From magnetic studies, the increase of magnetization is observed after Bi and Mn substitution up to (x = 0.4, (Bi) and y = 0.2 (Mn)) andthen adecrease in magnetization is noticed beyond(x = 0.4 and y = 0.2). A magnetization value of 3.1468 emu/g at an applied field of 20 K Oe, that is approximately twice that of the pure EuFeO₃, is obtained for the sample (x = 0.4(Bi) and y = 0.2 (Mn)). After evaluating the photocatalytic activity of these materials, Eu_1-xBi_xFe_1-yMn_yO₃ (0 ≤ x ≤ 0.4, 0 ≤ y ≤ 0.2) exhibited the best performance in photocatalytic applications. Additionally,the study revealed that local crystal field distortions create an environment conducive to photoluminescence in Eu³⁺ ions. These synthesized nanoparticles exhibit a combination of desirable properties that make them promising candidates for a wide range of commercial applications, particularly in the fields of photocatalysis and optoelectronics.

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The manufacturing of magnetic nanomaterials for production of green hydrogen is a promising answer to increasing difficulties of energy scarcity and environmental pollution. In this work, Co and Ga doped Ni-Zn-Cu catalysts, i.e., Ni_0.6Zn_0.1-xCu_0.3Co_xGa_yFe_2-yO₄ (x = y = 0.00–0.03) were fabricated via the inorganic sol-gel auto-combustion (SGAC) route. The development of cubic, aggregated, and spherical grains with in the range of 2 to 2.4 μm size were found through FESEM images. The M-H loops depicted the retentivity (M_r), coercivity (H_c), and saturation magnetization (M_s), in the range of 7.61–25.13 emu/g, 0.12–1.35 Oe, and 49.27 to 55.42 emu/g, respectively. When used for the photocatalytic production of hydrogen, the total hydrogen yield for the Ni_0.6Zn_0.1Cu_0.3Fe₂O₄ (x = y = 0.00), Ni_0.6Zn_0.09Cu_0.3Co_0.01Ga_0.01Fe_1.99O₄ (x = y = 0.01), Ni_0.6Zn_0.08Cu_0.3Co_0.02Ga_0.02Fe_1.98O₄ (x = y = 0.02), and Ni_0.6Zn_0.07Cu_0.3Co_0.03Ga_0.03Fe_1.97O₄ (x = y = 0.03) catalysts after four hours were 13.95, 14.15, 18.38 and (19.91 {rm{mmol}}{{rm{g}}}_{{rm{cat}}}^{-1}), respectively. The Ni_0.6Zn_0.07Cu_0.3Co_0.03Ga_0.03Fe_1.97O₄ (x = y = 0.03) photocatalyst displays the maximum photocatalytic efficiency of (19.91{rm{mmol}}{{rm{g}}}_{{rm{cat}}}^{-1}). However, the Ni_0.6Zn_0.08Cu_0.3Co_0.02Ga_0.02Fe_1.98O₄ (x = y = 0.02) specimen also shows the maximum electrocatalytic hydrogen evolution reaction (HER) rate. Hence, the cobalt and gallium doping played a significant role in enhancing the water splitting efficiency of Ni-Zn-Cu ferrites which holds great potential in green hydrogen generation.

When a surgeon replaces a damaged joint with an artificial implant, the risk of periprosthetic infection remains high. After surgery, metallic implants are vulnerable to periprosthetic joint infections due to corrosion. To mitigate biofilm formation, the materials and devices used as medical implants should be coated with films that provide both antimicrobial and anticorrosive properties, while also being cost-effective for the general patient population. This paper discusses the sol-gel synthesis of TiO₂-ZrO₂ thin films, stabilized at low temperatures, and intended for use as anticorrosion coatings on medical-grade steel. In this study, clinical-grade 316L flat substrates were coated with a TiO₂-ZrO₂ sol-gel solution via the spin-coating method under ambient conditions, followed by thermal treatment at 240 °C. Additionally, silver nanoparticles were synthesized in situ within the sol-gel solution to investigate their antibacterial properties. Characterization of the coatings’ anticorrosion performance revealed that the TiO₂-ZrO₂ films demonstrated up to 98% corrosion resistance, outperforming TiO₂-only coatings. The antimicrobial activity was assessed using the Kirby-Bauer disk diffusion method, evaluating the sensitivity of the pathogenic bacteria, Klebsiella pneumoniae and Klebsiella oxytoca with the TiO₂-ZrO₂-Ag nanoparticles films. The results indicated that silver nanoparticles exhibited antibacterial effects against both bacterial species, with clear inhibition zones surrounding the coated samples. For K. oxytoca, a greater sensitivity was observed, with an average inhibition zone of 19.1 ± 0.12 mm, whereas for K. pneumoniae, the inhibition zone was smaller, measuring 17.2 ±  0.3 mm.

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This study explores the structural, optical, and photocatalytic properties of Ti-doped ZnO (Zn₁₋ₓTiₓO) and its composite with reduced graphene oxide (rGO) for efficient dye degradation. The materials were synthesized via a hydrothermal method, with their structural characteristics analyzed through X-ray diffraction (XRD), transmission electron microscopy (TEM), and Raman spectroscopy. Ti incorporation into the ZnO matrix was confirmed, with doping concentrations up to 6 mol% causing a slight reduction in crystallinity. The Zn_0.94Ti_0.06O/rGO composite was successfully formed and its photocatalytic performance was assessed under various conditions, including photocatalyst loading, solution pH, and irradiation time. The composite demonstrated a remarkable 100% degradation of Coomassie Brilliant Blue R-250 (CBB R-250) dye under solar light, surpassing both undoped ZnO and Ti-doped ZnO. A reduced bandgap enabled enhanced visible-light absorption, while scavenger tests revealed that superoxide (O₂•⁻) and hydroxyl (OH•) radicals played pivotal roles in the degradation process. Cyclic tests confirmed the high stability and reusability of the Zn_0.94Ti_0.06O/rGO composite, highlighting its potential as an efficient, eco-friendly photocatalyst for dye removal.

This work presents the synthesis of Ni_0.5Cd_0.5Fe₂O₄ ferrite nanoparticle using the sol–gel method. X-ray diffraction (XRD) confirmed the formation of a cubic spinel phase (space group (Fdbar{3}m)), while Rietveld refinement and X-ray photoelectron spectroscopy (XPS) provided insights into cation oxidation states and site occupancies. Compared to undoped NiFe₂O₄, the Cd-substituted sample exhibited an expanded lattice parameter (a = 8.5190 Å) and larger crystallite size (D = 99 nm). Fourier-transform infrared (FTIR) spectra showed characteristic vibrational modes of tetrahedral and octahedral sites. Optical studies revealed broad UV–Vis–NIR absorption, a reduced direct bandgap of 2.13 eV, low Urbach energy (0.50 eV), a small extinction coefficient (~10⁻³), a favorable refractive index (2.33), enhanced optical conductivity, and improved dielectric properties. Magnetic measurements demonstrated a ferrimagnetic–paramagnetic transition at T_C = 470 K, soft magnetic behavior with low coercivity (19 Oe at 5 K; 9 Oe at 300 K), and moderate saturation magnetization (91.11 emu/g at 5 K; 54.35 emu/g at 300 K). Although Cd substitution reduced the magnetic performance compared to pristine NiFe₂O₄, it markedly enhanced optoelectronic efficiency by improving visible-light absorption, transparency, and energy conversion. The Ni_0.5Cd_0.5Fe₂O₄ sample demonstrates significant promise as a multifunctional material, particularly for applications in photocatalysis, solar energy conversion, and optoelectronics.

The advancement of stable energy storing devices with greater energy density (E_d) is a critical area of study that demands urgent focus. Supercapacitor (SC_s) exhibit considerable potential as viable solutions to these issues. Transition metal oxides (TMO_s) have attracted substantial interest due to their elevated energy density (E_d). In order to promote rapid electron/ion transit and prevent particle aggregation, a conductive, high-surface-area network was constructed using rGO. Although GdAlO₃ has redox-active sites that enable pseudocapacitance and its low intrinsic conductivity restricts its usefulness. This study introduces sonication technique for the synthesis of GdAlO₃/rGO nanosheets. The specific capacitance (C_s) of GdAlO₃/rGO was 1659.68 F/g at 1 A/g and GdAlO₃ (667 F/g) measured by three electrode configuration. Additionally, symmetrical behavior of GdAlO₃/rGO is demonstrated by two-electrode systems with C_s of 464.37 F/g with power density (1080 W/kg) at 1 A/g. GdAlO₃/rGO two-electrode configuration exhibits exceptional supercapacitive performance. GdAlO₃/rGO demonstrated remarkable symmetric two-electrode performance, achieving E_d of 18.80 Wh/kg at 1 A/g. This study suggests that the GdAlO₃/rGO possesses potential use in future energy storage systems.

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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