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Synthesis of Fluorescent Core-Shell Metal Nanohybrids: A Versatile Approach
摘要： A ?exible way of fabricating core-shell noble metal-organic nanohybrids with tailored chemical and spectroscopic properties is proposed here. The synthetic protocol consists of a multi-step procedure able to guarantee acceptable reproducibility of core size and shape as well as control of the organic outer layer. The proposed method highlights limitations in obtaining highly controllable products, although the heterogeneity degree of the nanostructures is in line with that expected from bottom-up approaches in solution. Selective functionalization of the nanohybrids with properly-substituted ?uorescent dyes under variable experimental conditions allowed the preparation of composite systems of tunable spectroscopic properties to be employed as nanoprobes in sensing or photonic applications. To this end, preliminary investigation on embedding the nanohybrids in compatible polymeric matrices is also reported.
关键词： polymeric matrix,spectroscopic properties,core-shell architecture,noble metal nanoparticles,self-assembly
更新于2025-09-04 15:30:14
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ZnO-coated SiO2 nanocatalyst preparation and its photocatalytic activity over nitric oxides as an alternative material to pure ZnO
摘要： Core-shell nanospheres, CSNp, consisting of silica as a core and zinc oxide as a shell were prepared via a simple and environmentally friendly procedure. Silica cores with a mean diameter of 300 nm were prepared through the hydrolysis-condensation reactions in the presence of hyperbranched poly(ethylene)imine (HBPEI) followed by calcination and chemical surface modi?cation with the use of HBPEI. To fabricate the core-shell structure, various amounts of zinc nitrate hexahydrate were precipitated using the carboxymethyl poly(ethylene)imine polymer (Trilon P) as a precipitator. To this suspension, the as synthesized modi?ed silica powder was added with the aim to develop electrostatic bonds between the carboxyl groups of TRILON P and the amino groups of the cationic HBPEI polymer. The optimization of processing parameters led to the development of homogeneous core-shell structures bearing a well-developed nanocrystalline zinc oxide shell over each silica core. The material with the optimum shell showed excellent photocatalytic activity over nitric oxides as the photocatalytic yield reached 72.9%.
关键词： Core-shell,Photocatalysis,Silicon oxide,Nitrogen oxides,Zinc oxide
更新于2025-09-04 15:30:14
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Poly(vinylidene fluoride)-based nanocomposite employing oriented Bi2S3 nanorods with double-shell structure for high dielectric performance and loss suppression
摘要： For polymer-based nanocomposites, designing the nanostructures of fillers, their distribution inside matrix as well as interfaces with the polymer is of crucial importance to achieve high dielectric performances. One-dimensional semiconductor Bi2S3 nanorods coated with homogeneous SiO2 and polydopamine (PDA) double shell layers were imported into the poly(vinylidene fluoride) (PVDF) with parallel arrangement via uniaxial stretching to form Bi2S3@SiO2@PDA/PVDF nanocomposite. The dielectric performances of oriented Bi2S3@SiO2@PDA/PVDF were studied in comparison with its counterparts employing Bi2S3 fillers without shell layers or alignment. A microcapacitor model was used to accurately estimate the dielectric constant along perpendicular direction. Coating conductive Bi2S3 nanorods with insulating SiO2@PDA double layer remarkably reduces the dielectric loss of the nanocomposite, while alignment of one-dimensional Bi2S3@SiO2@PDA nanorods endows electrical properties anisotropy, which was understood from J-V curves measured along two directions and moreover, via three-dimensional finite element analysis, unambiguously revealing the effects of aligned core-shell structured fillers on local electric field and current density distribution. This study provides a promising and facile approach for designing high performance dielectrics.
关键词： Polymer-matrix composites,Anisotropy,Numerical simulation,Dielectric performances,Ordered structure,Core-shell structure
更新于2025-09-04 15:30:14
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Direct storage of holes in ultrathin Ni(OH) <sub/>2</sub> on Fe <sub/>2</sub> O <sub/>3</sub> photoelectrodes for integrated solar charging battery-type supercapacitors
摘要： Energy storage is a very significant issue for utilization of solar energy due to its discontinuous and unstable energy flux. Herein, for the first time, we propose a Fe2O3@Ni(OH)2 core–shell nanorod array as a photoelectrochemical battery-type supercapacitor for the direct storage of solar energy. Under light illumination, Fe2O3 absorbs solar energy and produces electron–hole pairs, while Ni(OH)2 stores the photo-generated holes, which can be released as electricity when the light is switched off. In addition, by controlling the valence band position of the semiconductor and the thickness of Ni(OH)2, the side reaction of water oxidation (electrolyte decomposition), which is harmful for the applications of a photoelectrochemical supercapacitor, can be completely suppressed. As a consequence, the specific capacitance of the Fe2O3@Ni(OH)2 photoelectrochemical supercapacitor is enhanced up to 20.6 mF cm?2 at a discharge current density of 0.1 mA cm?2, which is about 4.5 times that of BiVO4/PbOx reported in a previous study. This study offers a very promising device for the direct storage of solar energy and deepens our understanding on the interface charge transfer between a photoelectrode and a battery-type capacitive material.
关键词： water oxidation suppression,Fe2O3@Ni(OH)2,photoelectrochemical supercapacitor,core–shell nanorod array,solar energy storage
更新于2025-09-04 15:30:14
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Chromium-Doped Zinc Gallogermanate@Zeolitic Imidazolate Framework-8: A Multifunctional Nanoplatform for Rechargeable In Vivo Persistent Luminescence Imaging and pH-Responsive Drug Release
摘要： Multifunctional theranostic nanoplatforms greatly improve the accuracy and effectiveness in tumor treatments. Much effort has been made in developing advanced optical-imaging-based tumor theranostic nanoplatforms. However, autofluorescence and irradiation damage of the conventional fluorescence imaging technologies as well as unsatisfied curative effects of the nanoplatforms remain great challenges against their wide applications. Herein, we constructed a novel core-shell multifunctional nanoplatform, i.e. chromium-doped zinc gallogermanate (ZGGO) near-infrared (NIR) persistent luminescent nanoparticles (PLNPs) as a core and zeolitic imidazolate framework-8 (ZIF-8) as a shell (namely ZGGO@ZIF-8). The ZGGO@ZIF-8 nanoplatform possessed dual functionalities of the autofluorescence-free NIR PersL imaging as well as the pH-responsive drug delivery, thus was highly expected in tumor theranostics. Notably, the loading content of doxorubicin (DOX) in ZGGO@ZIF-8 (?LC = 93.2%) was quite high, and the drug release of DOX-loaded ZGGO@ZIF-8 was accelerated in an acidic microenvironment such as tumor cells. The ZGGO@ZIF-8 opens up a new material system in the combination of PLNPs with metal–organic frameworks (MOFs) and may offer new opportunities for the development of advanced multifunctional nanoplatforms for tumor theranostics, chemical sensing, and optical information storage.
关键词： persistent luminescence imaging,metal–organic frameworks,core-shell nanostructure,pH-responsive drug delivery,tumor theranostics
更新于2025-09-04 15:30:14
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Fabrication and tribological characterization of deformation-resistant nano-textured surfaces produced by two-photon lithography and atomic layer deposition
摘要： In this study, we demonstrated a novel strategy for fabricating deformation-resistant nano-textured surfaces. Ordered arrays of IP-DIP photoresist nanodots of various diameters were first fabricated using two-photon lithography. IP-DIP/Al2O3 core-shell nanostructures (CSNs) were then formed by conformally coating the nanodots with Al2O3 of different thicknesses via atomic layer deposition (ALD). The CSNs showed 85% lower coefficients of friction than the bare IP-DIP nanodots and exhibited minimal nanostructure deformation at contact pressures greater than 20 GPa. The IP-DIP/Al2O3 CSNs also have lower adhesion forces than the bare IP-DIP nanodots. The excellent deformation resistance and superior tribological properties of these CSNs demonstrate that the combination of two-photon lithography and ALD is a very promising solution to tribological issues in miniaturized systems.
关键词： Surface Texturing,Atomic Layer Deposition.,Two-Photon Lithography,Core-Shell Nanostructures
更新于2025-09-04 15:30:14
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Sequential Growth of High Quality Sub-10 nm Core-Shell Nanocrystals: Understanding the Nucleation and Growth Process Using Dynamic Light Scattering
摘要： Monodisperse sub-10 nm core-shell nanocrystals have been extensively studied owing to their important applications in catalysis, bioimaging, nanomedicine and so on. In this work, an amorphous shell component-crystallization strategy has been proposed to prepare high quality sub-10 nm NaYF4:Yb/Er@NaGdF4 core-shell nanocrystals successfully via a sequential growth process. Dynamic light scattering technique has been used to investigate the secondary nucleation and growth process of forming the core-shell nanocrystals. The size and morphologies evolution of the core-shell nanocrystals reveal that the secondary nucleation of the shell component is unavoidable after hot-injecting of the shell precursor at high temperature, which followed by dissolution and re-crystallization process (an Ostwald Ripening process) to partially produce the core-shell nanocrystals. The present study demonstrates that the size of seed nanocrystals and the injection temperature of the shell component precursor play a vital role in formation of core-shell nanostructures completely. This work will provide an alternative strategy for precisely controllable fabrication of sub-10nm core-shell nanostructures for various applications.
关键词： Seed-mediated growth,Monodisperse,Core-shell nanoparticles,Dynamic light scattering
更新于2025-09-04 15:30:14
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Synthesis of core–shell ZIF-67@Co-MOF-74 catalyst with controllable shell thickness and enhanced photocatalytic activity for visible light-driven water oxidation
摘要： In this paper, a core–shell ZIF-67@Co-MOF-74 catalyst was synthesized by coating 2,5-dihydroxyterephthalic acid (DHTP) molecules on the surface of ZIF-67 crystals via the ligand exchange method. Notably, the ZIF-67@Co-MOF-74 catalyst with shell thicknesses of 10 nm, 25 nm and 50 nm can be further obtained by adjusting the mass ratio of ZIF-67 and DHTP. Compared to individual ZIF-67 or Co-MOF-74 catalyst, the as-prepared core–shell MOF catalyst exhibited enhanced photocatalytic activities for light-driven water oxidation reaction. Furthermore, the content of oxygen evolution by water splitting increased gradually with the increase in shell thickness. The formation of crystal defects and the uncoordinated hydroxyl and carboxyl groups on the surface of core–shell MOFs facilitated the exposure of the metal catalytic center and the adsorption of water molecules through hydrogen bonding interactions to react with the catalytic active center effectively. In addition, the photogenerated holes and electrons could be excellently separated and rapidly transferred at the interface of ZIF-67 (core) and Co-MOF-74 (shell), resulting in effective increase in the interfacial charge transfer rate. Furthermore, this simple and novel method is also applicable to three other carboxylic acid ligands, which implies that it may be a general method that can be extended to other ligands for fabricating different core–shell ZIF-67@MOF crystals.
关键词： ZIF-67@Co-MOF-74,ligand exchange method,water oxidation,core–shell,photocatalytic activity
更新于2025-09-04 15:30:14