Journal of Nanoparticle Research最新文献

Nanoparticles (NPs) exhibiting X-ray-excited UV-C luminescence can be used in radiation therapy to deactivate cancer cells through photochemical reactions of DNA with UV-C quanta. Colloidal solutions of monoclinic La_1−xPr_xPO₄ NPs (x = 0.01–0.3), luminescent in the UV-C range (220–280 nm), with different morphologies, from nanofiber (diameter and length not larger than 15 and 600 nm, respectively) to short nanorod (diameter and length not larger than 8 and 35 nm, respectively), were obtained by a microwave-assisted hydrothermal method. For possible biomedical use, the synthesis parameters (pH = 8, anion excess coefficient = 2) were determined, at which nanorods of suitable sizes (diameter and length not larger than 10 and 80 nm, respectively) with the brightest UV-C luminescence among all synthesized nanorods were obtained. A gradual increase in the optimal concentration of Pr³⁺ ions with maximum luminescence brightness from 4 mol-% for nanofibers to 6 mol-% for short nanorods was established. The shift of the intensity ratio of UV-C transitions toward the long-wave 4f¹5d¹→³H₆ transition was shown for nanofibers, whereas for nanorods all 4f¹5d¹→³H_4,5,6 transition intensities were approximately equal. A new laser ultramicroscopy method based on the detection of elastically scattered light with subsequent nanoparticle tracking analysis was used to calculate the hydrodynamic radii and to monitor the colloidal behavior of NPs in pH-modified aqueous media. The highest sedimentation and aggregation stability of NPs was found in an acidic medium (pH = 4), and temporary stability was also found in alkaline media (pH = 8, 10).

The traceability of GSR is critical in forensic investigations, as it can link a suspect to the use of a firearm. Traditional collection methods can make it challenging to visualize and document GSR patterns clearly in situ, particularly in dark or complex environments. This study investigates the synthesis, characterization, and application of ZnO Quantum Dots, synthesized using a modified sol–gel method, as fluorescent markers for the detection of GSR. This was then characterized using XRD, FTIR, UV–Vis spectroscopy, PL spectroscopy, TCSPC, and Thermogravimetric Analysis. XRD confirmed the high crystallinity of ZnO QDs with an average particle size in the range between 3–5 nm, TEM provided high-resolution images revealing uniform spherical nanoparticles, FT-IR identified functional groups and confirmed the chemical composition, UV–Vis spectroscopy determined the optical absorption properties, while PL spectroscopy showed a strong emission peak at 577 nm, indicating high fluorescence intensity, TCSPC measured the fluorescence lifetime and decay kinetics, revealing a lifetime of 5.9 ns and TGA assessed the thermal stability and decomposition temperatures. These nanoparticles were then incorporated into the propellant powders of various ammunition to evaluate their effectiveness as fluorescent markers for GSR. The tagged ammunition was fired and the obtained GSR imaged under UV light and VSC revealed the presence of yellow, fluorescent particles. The stability of the fluorescent signal was tested under various conditions, confirming the robustness of the material as GSR markers and proved as an effective tool providing an innovative approach for GSR detection that enhances the efficiency of crime scene investigations.

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Covalent organic frameworks (COFs) and TiO₂ nanotube arrays (TNTAs) have emerged as viable building blocks for solar-driven photocatalysis, owing to their distinct yet compatible structural and electronic properties. COFs offer consistent porosity, regular crystalline architectures, and modifiable band gaps through the intentional choice of organic linkers, enabling capable light absorption and molecular transport. Meanwhile, TNTAs provide uniformly oriented channels, significant area-to-volume ratios, and oriented conduction paths, which collectively enhance charge separation and reduce recombination rates. Integrating COFs and TNTAs into semiconductor-based photocatalysts creates closely interfaced heterojunction interfaces that leverage enhanced charge alignment and mutual enhancement, resulting in extended light harvesting, faster interfacial charge transfer, and greater photostability. This mini review evaluates recent advances in COF–TNTA composite design, synthesis strategies, and structure–function relationships, reports performance values across diverse systems, and discusses ongoing issues and potential developments for applicable, improved photocatalytic applications.

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This mini review explores the integration of covalent organic frameworks (COFs) and TiO₂ nanotube arrays (TNTAs) in solar-driven photocatalysis. COFs provide tunable porosity and bandgaps, while TNTAs enhance charge separation through their structured channels and large surface areas. These integrations into semiconductor-based photocatalysts improve light absorption, charge transfer, and photostability.

This study investigates the plasmonic behavior of an asymmetrically positioned nanodisk within a nanoring, revealing the activation of four distinct plasmonic modes within the wavelength range of 200- 2000 nm. By varying the asymmetry parameter, the distance between the centers of the nanodisk and nanoring, we observe remarkable sensitivity. We employ a straightforward model based on binary transformation in complex coordinates to delve into the extraordinary sensitivity of this system. Absorption cross-section analysis shows a progressive blue shift in three plasmonic bands with increasing asymmetry, while the fourth band, displaying a Fano-like resonance, remains stable. Notably, the first plasmonic mode exhibits an exceptional electric field enhancement factor of 71.5, generating an intense hotspot due to charge proximity in the nanodisk-nanoring gap. These results suggest that nanodisks integrated within nanorings offer a promising pathway for optimizing optical nanosensors.

The main objective of this study was to demonstrate adsorption of the ciprofloxacin (CIP) on NH₂-MIL-101(Fe)/silica xerogel composite. The composites were synthesized with varying loadings of NH₂-MIL-101(Fe) into the silica xerogel using the sol–gel method. The addition of NH₂-MIL-101(Fe) to silica xerogel structure increased the surface area up to 1092.8 m² g⁻¹. Optimum adsorption parameters including pH, contact time, and adsorbent dosage were optimized as 6.1, 180 min, and 0.3 g L⁻¹, respectively. Adsorption isotherm and kinetic models were implemented to equilibrium data. Langmuir isotherm and pseudo-second-order kinetic model well matched adsorption data. A high adsorption capacity of 185.2 mg g⁻¹ was obtained using a low adsorbent dosage at 298 K. The thermodynamic data exhibited that CIP adsorption on the composite was exothermic and spontaneous. The impact of ionic strength on adsorption was examined using NaCl and CaCl₂. The adsorption efficiency remained almost the same in presence of both monovalent and divalent cation. CIP adsorption was studied under the influence of dissolved organic matter, and adsorption efficiency decreased with increasing humic acid concentration. The adsorption-desorption cycles demonstrated the reusability of the composite, maintaining about 50% of its initial adsorption efficiency after four cycles.

The identification of the most favorable isomers is crucial for understanding non-classical clusters. For Be₅O₆²⁻ cluster, a recently reported structure ascribes the most favorable isomer as a star-shaped cyclic D_5h-Be₅O₆²⁻, contrasting to the previously claimed linear isomer. Our results reveal the key factors that determine the most favorable isomer, which are facilitated by an increase in orbital and electrostatic stabilizing terms that overcome the increase in steric repulsion, resulting in a more compact structure. Computationally evaluated ¹⁷O-NMR and aromatic characteristics, reveals a non-aromatic behavior. The current approach is useful for further understanding the preference between isomers in non-classical clusters.

This study investigates the energy characteristics of the adsorption layer formed on the surface of ZrO₂+3mol% Y₂O₃ nanopowder system under varying humidity conditions by thermogravimetry, electron microscopy, and nuclear magnetic resonance (NMR) spin-echo techniques. The spin–spin and spin–lattice relaxation times were determined at different relative ambient humidity. Our findings indicate slow relaxation of water molecules within the pore spaces of the samples, with a characteristic time parameter of 1.18 × 10^–7 s. Furthermore, a nonlinear relationship between desorption activation energy and humidity content was observed in the system. These results suggest the potential applicability of the investigated nano powder system as an adsorption device for energy storage purposes.

Recently, there has been considerable interest in utilizing the photocatalytic capabilities of semiconductor nanoparticles to degrade organic pollutants under sunlight. However, their post-treatment recovery remains a challenge. This study introduces a novel BiOCl/EVA nanocomposite film designed to simplify photocatalyst separation while maintaining high photocatalytic performance. BiOCl nanoparticles were synthesized via a co-precipitation method and embedded into an ethylene-vinyl acetate (EVA) matrix using a solvent casting technique. The resulting films were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy-dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), and UV-vis diffuse reflectance spectroscopy (DRS). The films demonstrated high crystallinity, thermal stability, and uniform nanoparticle dispersion. Optical analysis via Tauc plots revealed a suitable band gap for visible-light activation. Photocatalytic tests showed that approximately 98% of rhodamine B (RhB) dye was degraded under sunlight within 120 min. Additionally, the composite retained 88% of its efficiency after four reuse cycles, confirming its stability and reusability. Finally, through the use of experimental data and the trapping of active species, the degradation mechanism of RhB was elucidated. This work presents a promising, easily recoverable photocatalyst with strong potential for practical wastewater treatment applications.

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Hybrid nanoparticles (NPs), especially polyhedral oligomeric silsesquioxane (POSS) NPs, have emerged as efficient dopants for enhancing the electro-optic (EO) performance of liquid crystal (LC) devices. POSS NPs improve homeotropic alignment (HA) stability, reduce applied voltages, decrease ion density, and optimize dielectric properties, etc., leading to significant performance gains. In the present review, the analysis of reported EO studies shows a reduction in threshold (V_th) and operating (V_O) voltages by up to 25–35% and 20–30%, respectively, along with an enhanced contrast ratio (CR) of 40–60%. In addition, the response times improve markedly, with rise and fall times shortened by 20–50% compared with the undoped systems. Moreover, the dielectric anisotropy (Δε), conductivity suppression, and elastic constants are also favourably tuned. These improvements arise from POSS–LC molecular interactions and surface anchoring effects, which make the POSS-doped LC system potentially applicable to advanced displays, fast switching spatial light modulators (SLMs), tunable photonic devices, and low power EO components. Thus, the present work consolidates recent findings, provides comparative quantitative analysis, and highlights future opportunities for POSS-based nanocomposites in next-generation LC technologies.

Silica–ethylmaltol (EMA) nanoparticles (NPs) encapsulating {2,2′,2″,2‴-{4′-{[(4,6-dichloro-1,3,5-triazin-2-yl)amino]biphenyl-4-yl}-2,2′:6′,2″-terpyridine-6,6″-diyl}bis(methylenenitrilo)}tetrakis(acetate)–Eu³⁺ (DTBTA–Eu (III)) were prepared by the sol–gel method with the addition of EMA. The luminescence emission peak intensity of DTBTA–Eu (III) encapsulated in silica–EMA NPs increased with the amount of DTATB–Eu (III) from 0.4 to 9.6 µmol with the NP size maintained at 441 to 527 nm. The elution of EMA into distilled water led to the easy formation of silica nanocapsules (NCs) containing DTBTA–Eu (III) by controlling the immersion time. The remaining 12% of DTBTA–Eu (III) was bound to the interior of the silica NCs and the luminescence emission intensity of DTBTA–Eu (III) decreased from 293 to 32 at 614 nm after 2 days of immersion. The citrate ions added during the preparation of silica–EMA NPs encapsulating DTBTA–Eu (III) induced an electrostatic repulsion between silica NPs caused by negative charges of citrate ions on the silica NPs, resulting in a decrease in NP size from 616 (pm 22) to 329 (pm 15) nm, and the luminescence emission peak intensities of silica–EMA NPs encapsulating DTBTA–Eu (III) decreased from 950 to 250.