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EFFECT OF TEMPERATURE ON NANOCOMPOSITE OF METAL NANOPARTICLES IN PHOTONIC CRYSTALS
摘要： We theoretically investigate the photonic band gaps in one-dimensional photonic crystals based on nanocomposite of silver nanoparticles. The dielectric permittivity is calculated in accordance with temperature dependence of plasma frequency of silver nanoparticle. The effect of temperature on these structures by incorporating the volume expansion coefficient of nanoparticle is analysed. The behaviors of photonic band gaps with variation of filling factor, radii of nanoparticle and temperature are observed. The evolution of these results leads to designing the desired photonic crystals.
关键词： photonic crystals,nanocomposite,photonic band gaps,temperature dependence,silver nanoparticles
更新于2025-09-09 09:28:46
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Investigation of reinforced performance of modified graphene oxide/high solid content polysiloxane nanocomposite coating films
摘要： Graphene oxide was modi?ed using long-chain silicone. The modi?ed graphene oxide (MGO) was obtained with a broader spacing of layers (1.45 nm) which means more bene?cial to polysiloxane entering into the laminates of MGO sheets. Then, MGO sheets were combined with polysiloxane which synthesized without any organic solvent to prepare nanocomposite coatings via cross-linking curing reaction. The solid content of polysiloxane can be reached up to 86%. Due to strong interfacial interaction and synergistic reinforcing between MGO sheets and polysiloxane, when blended with 1.00 wt% of MGO, the micro-hardness and elastic modulus of coating ?lms were increased by 57% and 24% comparing with pure polysiloxane coating ?lm, respectively. Subsequently, a 48% improvement of macro-scratch resistance can be achieved. Simultaneously, MGO/polysiloxane coating ?lm showed excellent wear resistance due to the unique two-dimensional geometry and low frictional coef?cient of MGO sheets at work in homogeneous dispersion system.
关键词： Polysiloxane,Scratch resistance,Wear resistance,Nanocomposite coatings,Graphene oxide
更新于2025-09-09 09:28:46
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Metalloporphyrins-sensitized titania-silica-iron oxide nanocomposites with high photocatalytic and bactericidal activities under visible light irradiation
摘要： Multifunctional photocatalyst system of meso-tetra(4-carboxyphenyl)porphyrin (TCPP) with different metal centers [Mn(II), Fe(III), Cu(II), Zn(II) and metal-free] adsorbed on titania-silica-iron oxide magnetic photocatalyst nanocomposites (TSI) that united superparamagnetic behavior and high photoactive activity under visible light irradiation have been prepared. The superparamagnetic nanocomposites have been characterized and analyzed using UV-visible absorption spectroscopy, X-ray diffractometry (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The results showed that copper(II)tetra(4-carboxyphenyl)porphyrin -sensitized titania-silica-iron oxide nanocomposites (CuTCPP-TSI) can effectively degrade methylene blue (MB) and kill Escherichia coli (E. coli) under irradiation with an incandescent lamp. The magnetic photocatalysts could be used at least four times without regeneration. Therefore, the CuTCPP-TSI nanocomposites can be applied in catalytic photodegradation and used for magnetically-guided antibacterial applications.
关键词： Metalloporphyrin,Nanocomposite,Magnetic,Titania,Photocatalyst
更新于2025-09-09 09:28:46
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Microwave-Assisted Hydrothermal Synthesis of ZnFe<sub>2</sub>O<sub>4</sub>/TiO<sub>2</sub> Composite and Photocatalytic Properties
摘要： In order to improve TiO2 photocatalytic activity ZnFe2O4/TiO2 nanocomposites with different ZnFe2O4 mass loading were produced. Obtained ZnFe2O4 nanoparticles were coupled with TiO2 via microwave-assisted hydrothermal method in order to improve photon absorption in a range of visible light. Prepared nanostructures were characterized with scanning electron microscopy and X-ray diffraction. Photocatalytic activity of prepared samples was investigated by degradation of methylene blue under different light sources – LED, Hg and Osram Vitalux lamps. ZnFe2O4 consisted of spherical nanoparticles with average size of 15 nm. TiO2 spherical nanoparticles size was in a range of 30÷45 nm. The results shown that doping TiO2 with ZnFe2O4 nanoparticles increased photocatalytic activity. Photocatalytic activity increases as mass loading of ZnFe2O4 decreased.
关键词： titania,zinc ferrite,hydrothermal,photocatalysis,nanocomposite
更新于2025-09-09 09:28:46
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A Novel approach for synthesis of LaFeO3/Bentonite Nanocomposite for degradation of methylene blue with enhanced photocatalytic activity” for publication in your esteemed Journal “Materials research express
摘要： Bentonite supported LaFeO3, an active photo catalyst nanocomposite(NC) was synthesized by citric acid assisted sol-gel method and the photocatalytic activity of synthesized NC is conversed. From the TG-DSC studies, it is prominent that the NC exhibited a little mass gain after600°C from which the calcination temperature for preparing NC was decided. The characterization process of photocatalysts was estimated through Fourier transform infrared (FTIR) spectroscopy, Powder X-ray diffraction (PXRD) studies and Scanning electron Microscopy (SEM). The energy band gap studies were carried out for all the synthesized samples using UV-Vis diffuse reflectance spectroscopy. The photocatalytic activities of all the synthesized samples were evaluated by degrading Methylene Blue (MB) under visible light irradiation. The synthesized LaFeO3/Bentonite (2.5) NC exhibited remarkable and excellent photocatalytic activity with the overall removal rate of MB upto95% for 60 min. The abundant hydroxyl groups of Bentonite and the combination of photocatalytic and photo-Fenton like mechanism of LaFeO3/Bentonite (2.5) could enhance the photocatalytic degradation. Therefore, the LaFeO3/Bentonite is a very promising photocatalyst in future industrial application to treat the dye wastewater.
关键词： Methylene blue,phototocatalytic,Nanocomposite,Photo-Fenton
更新于2025-09-09 09:28:46
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A new photocatalyst based on Co(CO3)0.5(OH)·0.11H2O/Bi2WO6 nanocomposites for high-efficiency cocatalyst-free O2 evolution
摘要： The practical application of photocatalytic water splitting is essentially limited by the slow kinetic nature of the water oxidation process. Therefore, it is highly desirable but challenging to explore a low-cost and high-efficiency water oxidation catalyst for the aim of commercialization and industrialization. We herein report the first-time synthesis of a novel and high-efficiency visible-light-driven photocatalyst composed of flower-like Co(CO3)0.5(OH)·0.11H2O (CCO) nanowires and Bi2WO6 (BWO) nanosheets, i.e. CCO/BWO nanocomposite, via a facile hydrothermal method. Without utilizing any additional cocatalyst, the composite of CCO/BWO in 30% weight ratio exhibits extraordinarily high photoactivity and photostability towards O2 evolution, achieving an average O2 generation rate of 953 μmol h?1 g?1 under visible-light irradiation (λ > 420 nm).
关键词： Bi2WO6,Nanocomposite,Cocatalyst-free,Photocatalytic O2 evolution,Co(CO3)0.5(OH)·0.11H2O
更新于2025-09-09 09:28:46
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Halloysite based nanocomposites and photocatalysis: A Review
摘要： Heterogeneous photocatalysis is an e?cient, relatively cheap and environmentally friendly technology for decomposing various organic and air pollutants. Halloysite is a natural clay mineral usually in the form of nanotubes that has many applications as well as potential uses including photocatalysis. In this paper the photocatalytic activities of halloysite-based nanocomposites in combination with various photocatalysts that have been synthesized and tested in decomposing organic and air pollutants are reviewed. Many photocatalysts have been synthesized and among them TiO2 in the form of anatase, or rutile, or a mixture of both is the most common photocatalyst due to its e?ectiveness and low cost. Researches by many investigators are summarized and discussed. The possibilities and limitations of halloysite-based nanocomposites for future applications are also discussed and new ?elds of research are proposed. It is suggested that Halloysite-based nanocomposites are more promising in positively charged organic substrates like tetracycline and Rhodamine B where the organic pollutant is attracted by halloysite's negatively charged external surfaces close to the photocatalysts, than neutral like paracetamol or negatively charged which that attraction does not occur.
关键词： Azo dyes,Halloysite nanocomposite,Halloysite,TiO2,VOCs,Heterogeneous catalysis,Air pollutants,Photocatalysis
更新于2025-09-09 09:28:46
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[IEEE 2017 IEEE 12th Nanotechnology Materials and Devices Conference (NMDC) - Singapore (2017.10.2-2017.10.4)] 2017 IEEE 12th Nanotechnology Materials and Devices Conference (NMDC) - Measurements of Polyimide/Silicon Nitride nanocomposite interphase
摘要： According to recent studies on electrical insulation systems, the nanocomposite organic/inorganic hybrid materials (NC) assure a distinct improvement of their high-temperature functioning and allow strengthening the dielectric properties of these systems. Recently it was shown that some modifications of the electrical properties such as the permittivity, dielectric breakdown and materials lifetime, were often awarded to the properties of what it is called the interphase. This interphase represents the interaction zone between the nanoparticles and the matrix and plays very often a leading part in the definition of the macroscopic properties. In this paper, Atomic Force Microscopy (AFM) is used to make, at the same time, qualitative and quantitative measurements of these interaction zones. For example, Peak Force Quantitative Nano Mechanical (PF QNM) mode, would allow to highlight the presence of the interphase by measuring mechanical properties (Young’s modulus, deformation and adhesion). As a result, this new and original study on Polyimide/Silicon Nitride (PI/Si3N4) nanocomposite confront experimental results with theoretical models.
关键词： Polyimide,PF-QNM,AFM,Nanocomposite,Si3N4 nanofillers,Interphase,Nanodielectrics
更新于2025-09-09 09:28:46
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Near-Room-Temperature Ethanol Gas Sensor Based on Mesoporous Ag/Zn-LaFeO <sub/>3</sub> Nanocomposite
摘要： The rational design of heterojunction between different metal oxides with mesoporous structures has attracted tremendous attention due to their special physicochemical properties and vital importance for practical applications. In this paper, mesoporous Ag/Zn–LaFeO3 nanocomposite is successfully synthesized through a facile nanocasting technique using KIT-6 as a hard template in sol–gel route and used as sensing materials to achieve an exceptionally sensitive and selective detection of trace ppm-level ethanol. The obtained composite possesses high surface area and exhibits excellent sensing response (64.2 for 100 ppm) to ethanol at near-room with relatively fast response/recovery time. When tested with the concentrations as low as 5 ppm, it also shows a remarkably high selectivity to the ethanol, but only minor responses to other interfering gases. These enhanced gas-sensing properties are attributed to the combination of mesoporous nanostructure and Ag/Zn–LaFeO3 heterogeneous composites.
关键词： mesoporous,ethanol,gas sensors,near-room temperature,Ag/Zn–LaFeO3 nanocomposite
更新于2025-09-09 09:28:46
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High-gravity-assisted scalable synthesis of zirconia nanodispersion for light emitting diodes encapsulation with enhanced light extraction efficiency
摘要： Zirconia-based hybrid polymers has become one of the ideal encapsulation material for light emitting diodes (LEDs) with high extraction efficiency due to their proper refractive index to those of semiconductor chips. However, the controlling of the dispersion for zirconia nanoparticles in polymeric hosts to obtain optically transparent hybrid nanocomposites has been one of the major challenges. Herein, we reported the synthesis of zirconia nanodispersion via high-gravity-assisted homogeneous precipitation in an internal circulation rotating packed bed (RPB) reactor followed by two-step modification. An alternative to conventional precipitation in batch stirred tank reactors (STR), the process intensification by high-gravity RPB results in homogeneous micromixing during the nucleation and growth of zirconia particles, which are benefit for continuous and reproducible production of ultrasmall zirconia nanoparticles. The obtained zirconia nanoparticles are purely cubic phase with narrow size-distribution in the range of 3–5 nm according to the X-ray diffraction and transmission electron microscopy characterization, which were similarity to that by the conventional methods. Nevertheless, the average hydrodynamic diameters of zirconia nanoparticles in aqueous solutions obtained by RPB methods were much smaller than those prepared in conventional STR, which enabled easy control and surface modification for highly dispersed nanodispersion in organic solvents and/or polymeric hosts. After two-step surface modification, zirconia nanoparticles with goal-directed structures were obtained, with highly dispersity in various organic solvents (e.g. toluene, trichloromethane, tetrahydrofuran, etc.) and aliphatic epoxy resin, forming transparent hybrid films with tunable refractive indexes. The preliminary applications of these zirconia nanodispersions for LEDs encapsulation were demonstrated. The light extraction efficiency of the LEDs devices packaged with zirconia/epoxy hybrid material increased by 10 percent when the doping content of zirconia nanoparticles was 0.2, compared to the devices encapsulated by original epoxy.
关键词： Rotating packed bed,Hybrid nanocomposite,Zirconia nanoparticles,LED encapsulation
更新于2025-09-09 09:28:46