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Investigations on structural, optical and electrical property of ZnO-CuO core–shell nano-composite
摘要： ZnO-CuO core–shell nano-composite was synthesized by two-stage assisted wet-chemical sol-gel method. The nano-composite investigated by X-ray diffraction, ?eld effective scanning electron microscope, UV–visible spectroscopy and Electrical property at different frequency range 100 Hz to 2 MHz and at different temperature. The X-ray diffraction pattern shows poly-crystalline growth of sample, UV–visible spectrum shows higher absorption in ZnO-CuO nano-composite as compare ZnO, which can be understood in vicinity of morphology and heterojunction. The electrical conductivity of nano-composite has been increased with frequency and temperature due to defect available in the sample and thermal excitation of the charges in the sample respectively.
关键词： Nano-composite,Sol–gel,Core–shell,AC conductivity
更新于2025-11-14 17:28:48
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Multi-layer CeO2-wrapped Ag2S microspheres with enhanced peroxidase-like activity for sensitive detection of dopamine
摘要： A novel core-shell structure Ag2S@CeO2 microspheres were synthesized by growing multi-layer CeO2 onto Ag2S particles. Compared with pure Ag2S, the resultant composite catalyst exhibited highly improved peroxidase-like activity. Influences of pH, temperature, H2O2 concentration and the amount of catalyst on the catalytic activity of Ag2S@CeO2 were investigated. Besides, Ag2S@CeO2 displayed a strong affinity towards H2O2 and 3,3',5,5'-tetramethylbenzidine (TMB). Based on the excellent peroxidase-like activity of Ag2S@CeO2 microspheres, a highly sensitive and selectivity colorimetric method for dopamine detection was developed. The possible catalytic mechanism was also studied using fluorescent probe analysis. It is believed that the efficient biosensor based on the as-prepared Ag2S@CeO2 microspheres can apply for biological analysis and environmental monitoring.
关键词： Core-shell,Ag2S,CeO2,Peroxidase,Dopamine
更新于2025-11-14 17:15:25
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Rapid gas-liquid detonation synthesis of core-shell structural graphite coated TiO2 nanoparticles
摘要： Here we demonstrate a simple, rapid for the controlled synthesis of core-shell structural graphite coated TiO2 nanoparticle (TiO2@G), which are directly prepared by detonation chemical decomposition of the gas-liquid mixture of CH4, O2, C6H6 and TiCl4 in milliseconds. Various techniques, including XPS, TEM, XRD and Raman were employed to investigate the products. It is found that the sphere, good disperse mixed crystal TiO2 nanoparticles with crystal size of 10–30 nm were coated with thick graphite layers. Based on Zeldovich Neuman-Doring (ZND) model, the detonation synthesis mechanism of core-shell structure TiO2@G is discussed. This rapid synthesis method can be extended to the preparation of other core-shell materials.
关键词： Gas-liquid detonation,Graphite coated TiO2,Core-shell structure,Composite materials,Formation mechanism
更新于2025-11-14 17:04:02
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Conductive electrodes based on Ni–graphite core–shell nanoparticles for heterojunction solar cells
摘要： Ni–graphite core–shell nanoparticles (CSNPs), which consisted of Ni nanoparticles (NPs) wrapped with several graphene layers, were grown by the thermal reduction of NiO NPs using H2. The effect of the synthesis temperature (800, 900, 1000, and 1100 °C) on the formation of multilayer graphene shells on the Ni core NPs was investigated to evaluate the structural and electrical characteristics of the particles. The proposed chemical reactions for the formation of Ni NPs can be summarized as follows: formation of liquid Ni by the reduction of NiO, thermal decomposition of the NiO phase, and formation of multilayer graphene shell because of the supersaturation of C in the liquid Ni phase. The resistivity of the electrode pattern fabricated with the Ni–graphite CSNP paste was found to be 6.75 × 10?3 ?·cm. Further, the power conversion efficiency of bulk heterojunction solar cells fabricated with the Ni–graphite CSNPs is higher than that of cells fabricated without the Ni- graphite CSNPs. Thus, our Ni–graphite CSNPs can be employed as a highly efficient electrode material in bulk heterojunction solar cells.
关键词： Thermal reduction,Core–shell structure,Nickel oxide nanoparticle,Graphite,Graphene
更新于2025-11-14 17:04:02
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Improving Photovoltaic and Enzymatic-Sensing Performance by Coupling Core-Shell Au Nanorod@TiO2 Heterostructure with Bioinspired L-DOPA Polymer
摘要： The photoelectrochemistry (PEC) performance of TiO2 is somewhat limited by its wide band gap and low quantum efficiency, and the innovation of its composite materials provides a promising solution for an improved performance. Herein, a composite of an Au nanorod@TiO2 core-shell nanostructure (AuNR@TiO2) and a melanin-like L-DOPA polymer (PD) is designed and prepared, where the outer-layer PD tethered by the TiO2-hydroxyl complexation and the AuNR core can intensify the long-wavelength light harvesting, and the AuNR@TiO2 core-shell structure can strengthen the hot-electron transfer to TiO2. The photocurrent of the PD/AuNR@TiO2 is 8.4-fold improved versus that of commercial TiO2, and the maximum incident photon-to-electron conversion efficiency reaches 65% in the UV-visible-near-infrared region. In addition, the novel PD/AuNR@TiO2 photocatalyst possesses the advantages of good biocompatibility and stability, which can act as a versatile PEC biosensing platform for providing biocompatible environment and improving detection sensitivity. Herein, a PEC enzymatic biosensor of glucose is developed on the basis of the immobilization of dual enzyme (glucose oxidase (GOx) and horseradish peroxidase (HRP)) in PD and the signalling strategy of biocatalytic precipitation. In phosphate buffer containing glucose and 4-chloro-1-naphthol, the HRP-catalyzed oxidation of 4-chloro-1-naphthol by GOx-generated H2O2 can form a precipitate on the electrode, by which the decrement of photocurrent intensity is proportional to the common logarithm of glucose concentration. The linear detection range is from 0.05 μM to 10.0 mM glucose, with a limit of detection of 0.01 μM (S/N=3). Glucose in some human serum samples is analyzed with satisfactory results.
关键词： Au nanorod@TiO2 core-shell heterostructure,biocatalytic precipitation,bioinspired L-DOPA polymer,photoelectrochemistry,enzymatic sensing of glucose
更新于2025-11-14 17:04:02
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ZIF-8@H:ZnO Core-shell nanorods arrays/Si heterojunction self-powered photodetector with ultrahigh performance
摘要： The native defects will degrade the performance and stability of the optoelectric device. Herein, a zeolitic imidazolate framework-8 (ZIF-8)@H:ZnO core-shell nanorods arrays/Si heterojunction self-powered photodetector is demonstrated. Combining hydrogenation and ZIF-8 passivation, its photoresponsive characteristics are greatly enhanced. The photodetector exhibits superior detectivity of ~2.14×1016 Jones (1 Jones=1 cm Hz1/2 W-1), high responsivity of ~7.07×104 mA W-1, prominent sensitivity of ~2.08×1012 cm2 W-1 and broadband photodetection ranging from the ultraviolet to the near infrared. As critical figures of merit, its responsivity increases by nearly 5 orders of magnitude than that of pristine ZnO nanorods arrays/Si heterojunction photodetector. More importantly, the comprehensive performance of ZIF-8@H:ZnO core-shell nanorods arrays/Si heterojunction photodetector not only achieves a record high value for ZnO-based photodetectors reported so far, but also can be comparable with that of two-dimensional (2D) materials, zero-dimensional (0D) materials, topological insulators, perovskites and other oxides based self-powered photodetectors. The novel post-treatment strategy has great potential in developing high-performing self-powered photodetectors. Meanwhile, this work may be extended to other oxides based optoelectronic devices.
关键词： core-shell nanorods,heterojunction,passivation,self-powered photodetector,ZnO,ZIF-8,hydrogenation
更新于2025-11-14 17:04:02
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Synthesis, characterization and dye sensitized solar cell application of Zinc oxide based coaxial core-shell hetrostructure.
摘要： In the present work, the ZnO/CdS coaxial core shell hetrostructure has been synthesized on indium doped tin oxide glass substrate using chemical solution methods and further it is used as photoanode in the DSSC application. Four samples with different concentration of sulphur source were prepared. An approximate crystallite size of 22 nm for ZnO and 18 nm for CdS has been obtained as analyzed from X-ray diffraction data. FESEM and HRTEM images confirm the formation of CdS shell on ZnO nanorods with a width below 100 nanometer. UV-visible spectroscopy and photoluminescence spectroscopy were used to examine the optical response revealing the fact that band gap reduction and a small red shift takes place for core shell structure as compared to bare ZnO nanorods array. The J-V characterization was performed to study the photovoltaic response. An improved efficiency was observed for core shell ZnO/CdS hetrostructure (3.66%) as compared to bare ZnO nanorods based DSSCs (0.70%). This improvement is due to increased current density caused by reduced recombination of photogenerated electron hole pairs. This reduced recombination is achieved by two factors, one is formation of type two core shell hetrostructure and second is increasing sulphur concentration in shell structure.
关键词： DSSC,Hetrostructure,FESEM,HR-TEM,coaxial core-shell
更新于2025-11-14 17:04:02
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MOF-templated core-shell Co(II/III)@ZnO hexagonal prisms for selective oxidation of vanillyl alcohol
摘要： This work provides a facile strategy to prepare core-shell structured catalysts with MOF-templated metal active species embedded carbon matrix core and a functional metal oxide shell in a controllable way. The procedure features with the facile introduction of functional shell metal oxide and delivery of MOF morphology. Co(II/Ⅲ)@ZnO hexagonal prisms are fabricated with this procedure and ZIF-67 as the template. When being used in the selective oxidation of vanillyl alcohol to produce vanillin, ZnO shell plays an important role by faciliating redox of Co3+/Co2+ for promoting vanillyl alcohol oxidation to vanillin and protecting the Co species against leaching into the reaction system. Co(II/Ⅲ)@ZnO exhibits a conversion of 20% with a selectivity of 80% after a 2 h reaction and shows stability after 3 catalytic cycles.
关键词： selective oxidation,vanillin,MOF-templated,ZnO,core-shell
更新于2025-11-14 17:03:37
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NiS2@MoS2 Nanospheres Anchored on Reduced Graphene Oxide: A Novel Ternary Heterostructure with Enhanced Electromagnetic Absorption Property
摘要： For the purposes of strength, military equipment camou?age, and protecting the health of organisms, electromagnetic wave absorbing materials have received a lot of attention and are widely studied. In addition to having a strong absorption intensity and a wide effective absorption bandwidth, materials that are lightweight, thermally stable, and antioxidative are also highly desirable. In this study, we fabricated core–shell structured NiS2@MoS2 nanospheres anchored on reduced graphene oxide (rGO) nanosheets (NiS2@MoS2/rGO) by a simple two-step hydrothermal method. The combination ratio was adjusted to achieve proper impedance matching. The electromagnetic parameters and the absorption performance were investigated in detail. A composite loaded with 30 wt.% of the sample achieved a minimum re?ection loss (RL) value of ?29.75 dB and the effective bandwidth (RL value of less than ?10 dB) ranged from 4.95 GHz to 18.00 GHz (13.05 GHz), with a thickness ranging from 1.5 mm to 4.0 mm. This study proved that the generated signi?cant interfacial polarization and synergetic interaction between components can result in NiS2@MoS2/rGO composites with enhanced electromagnetic absorption performance.
关键词： heterostructure,electromagnetic absorption,graphene,core–shell
更新于2025-11-14 17:03:37
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<p>A multifunctional-targeted nanoagent for dual-mode image-guided therapeutic effects on ovarian cancer cells</p>
摘要： Nanomedicine has emerged as a novel therapeutic modality for cancer treatment and diagnosis. Lipid–polymer hybrid nanoparticles (LPHNPs) are core–shell nanoparticle (NP) structures comprising polymer cores and lipid shells, which exhibit complementary characteristics of both polymeric NPs and liposomes. However, it is difficult to wrap perfluoropentane (PFP) into core–shell NPs in the existing preparation process, which limits its application in the integration of diagnosis and treatment. Methods: The folate-targeted LPHNPs-loaded indocyanine green/PFP-carrying oxygen (TOI_HNPs) using a combination of two-step method and solution evaporation technique for the first time. The essential properties and dual-mode imaging characteristics of developed NPs were determined. The cellular uptake of TOI_HNPs was detected by confocal microscopy and flow cytometry. The SKOV3 cell viability and apoptosis rate were evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay and flow cytometry. The ROS was demonstrated by fluorescence microplate reader and the expression of hypoxia-inducible factor 1-alpha (HIF-1α) and IL-6 was detected by Western blot. Results: TOI_HNPs showed spherical morphology with particle size about (166.83±5.54) nm and zeta potential at -(30.57±1.36) mV. It exhibited better stability than lipid NPs and higher encapsulation efficiency as well as active targeting ability than poly (lactic-co-glycolic acid) (PLGA) NPs. In addition, the novel NPs could also act as the contrast agents for ultrasound and photoacoustic imaging, providing precision guidance and monitoring. Furthermore, TOI_HNPs-mediated photo–sonodynamic therapy (PSDT) caused more serious cell damage and more obvious cell apoptosis, compared with other groups. The PSDT mediated by TOI_HNPs induced generation of intracellular ROS and downregulated the expression of HIF-1α and IL-6 in SKOV3 cells. Conclusion: This kind of multifunctional-targeted nanoagent may provide an ideal strategy for combination of high therapeutic efficacy and dual-mode imaging guidance.
关键词： core-shell nanoparticle,ultrasound,photo-sonodynamic therapy,phase transformation,photoacoustic imaging,laser
更新于2025-11-14 17:03:37