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PHOTOCATALYTIC REMOVAL OF PHENOL OVER MESOPOROUS ZnO/TiO2 COMPOSITES
摘要： A series of mesoporous ZnO/TiO2 composites were successfully synthesized using cetyltrimethylammonium bromide surfactant. The composites of different Zn:Ti molar ratios (0.5:1, 0.75:1, and 1:1) were prepared by impregnating ZnO onto mesoporous TiO2. XRD results verified co-existence of both anatase TiO2 and hexagonal wurtzite ZnO in the ZnO/TiO2 composites. Based on the Tauc plots, all the composites showed almost the same band gap energy of approximately 3.21 eV. The fourier transform infrared spectroscopy results successful covering of ZnO on the surface of the TiO2 as the hydrophilicity property of TiO2 decreased remarkably with the loading of ZnO in the composites. N2 adsorption-desorption isotherms of the samples exhibited type-IV isotherm with a hysteresis loop. The Barrett-Joyner-Halenda pore size distribution revealed that the average pore size of the composites was around 3.6 nm, indicating the formation of mesopores dominantly in the samples. The photocatalytic removal of phenol over the samples under UV light irradiation after 3 h decreased in the order: ZnO/TiO2 composites > anatase TiO2 (with surfactant) > anatase TiO2 (without surfactant) > ZnO. The composite with Zn:Ti molar ratio of 0.75:1 has achieved the highest photocatalytic activity of 36.5% in the removal of phenol under UV light irradiation for 3 h.
关键词： photocatalytic activity,ZnO/TiO2 composites,phenol,ZnO,TiO2
更新于2025-09-23 15:21:01
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Hybrid Ceramo-Polymeric Nano-Diamond Composites
摘要： This paper discusses a new class of bio-mechanical scaffolds active for tissue engineering based on a nano-diamond-filled hydrophilic polymer matrix. The new biomaterials used have special mechanical and biological properties for which they should be extensively studied for their use for various advanced biomedical applications. The new hybrid material has been prepared using 2 and 5% by volume of detonating nano-diamonds and poly (hydroxy-ethyl-methacrylate) hydrophilic. Both the mechanical and biological properties specific to the nanocomposite are hybrids in nature. The paper presents the analytical procedures of the hybrid material and the preliminary mechanical characterization. This class of hybrid materials has a high potential for biomimetic, osteoconductive and osteoinductive applications as active bio-mechanical bones for increasing osteoblasts and differentiating stem cells. At the same time, these hybrid nano-composites possess a much improved mechanical strength that exceeds the mechanical deficiencies of the hydrogels traditionally used for bone regeneration and can be applied as an osteoinductive coating for metal trabecular scaffolds. Micro-trabecular metal structures coated with active and osteoinductive biomechanical ceramic-polymeric biomechanical scaffolds are proposed to recreate macro and micro-distribution of bone stresses and deformations.
关键词： Biomaterials,Biomimetic,Nano-Composites
更新于2025-09-23 15:21:01
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Up-Conversion Luminescence Properties of Lanthanide-Gold Hybrid Nanoparticles as Analyzed with Discrete Dipole Approximation
摘要： Up-conversion nanoparticles (UCNP) under near-infrared (NIR) light irradiation have been well investigated in the field of bio-imaging. However, the low up-conversion luminescence (UCL) intensity limits applications. Plasmonic modulation has been proposed as an effective tool to adjust the luminescence intensity and lifetime. In this study discrete dipole approximation (DDA) was explored concerning guiding the design of UCNP@mSiO2-Au structures with enhanced UCL intensity. The extinction effects of gold shells could be changed by adjusting the distance between the UCNPs and the Au NPs by synthesized tunable mesoporous silica (mSiO2) spacers. Enhanced UCL was obtained under 808 nm irradiation. The original theoretical predictions could not be demonstrated to full extend by experimental data, indicating that better models for simulation need to take into account in homogeneities in particle morphologies. Yet, one very certain conclusion resulting from the DDA calculations and experiments is that the absorbance can blue-shift with more Au NPs added and the absorbance can-red shift for samples with enhanced silica sizes in the UCNP@mSiO2-Au structures. Furthermore, when the DDA model is more consistent with the practical structure (dispersed Au NPs instead of Au shell), the theoretical absorbance occurs almost the same as the practical absorbance. All in all, the DDA could fit the extinction effect of Au perfectly and be suitable for guiding how to design the UCNP and Au.
关键词： lanthanide-based composites,surface plasmon resonance,up conversion nanoparticles,discrete dipole approximation
更新于2025-09-23 15:21:01
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[IEEE 2018 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - Saint Petersburg, Russia (2018.10.22-2018.10.23)] 2018 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - Porous Silicon as a Material for Nanocomposites and the Effect of its Parameters on the Morphology of Silver Clusters
摘要： On the example of the por-Si/Ag composites it is demonstrated the ability to control the morphology of the guest material (Ag) by changing the parameters of the porous media (por-Si). Two groups of key parameters of porous materials important for creating composites based on them are discussed. Porous silicon was obtained by electrochemical anodic etching. The introducing Ag into the pores was performed by the cathodic electrochemical deposition. It is observed the increasing the anodizing time is leads to the noticeably changes of wetting angle of por-Si, and, in turn, significantly affects the morphology of Ag clusters. The growth mechanisms of Ag clusters on the por-Si surface and the fields of its potential application are discussed.
关键词： porous texture,surface properties,porous silicon composites,por-Si/Ag composites,electrochemical deposition,surface functionality,silver clusters
更新于2025-09-23 15:19:57
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Metal organic frameworks composite Eu2O3@[Zn2(1,4-ndc)2dabco] synthesized by pulsed laser ablation in flowing liquid and its fluorescent sensing of fatty alcohol with different branch chains
摘要： This work reports the metal organic frameworks composite Eu2O3@[Zn2(1,4-ndc)2dabco] synthesized by pulsed laser ablation in flowing liquid. Powder X-ray Diffraction (PXRD) and SEM were used to characterize its structure and morphology. The results show that the Eu2O3 nanoparticles with the average particle size of 3.08 nm are uniformly distributed among the crystal and the BET specific surface area of the composite Eu2O3@[Zn2(1,4-ndc)2dabco] is 1087 m2/g. At 296 K, the adsorption capacities of C2H2 on composite are up to 117.3 cm3/g, which is larger than that of the compound [Zn2(1,4-ndc)2dabco]. The C2H6/CH4 selectivity of the composite Eu2O3@[Zn2(1,4-ndc)2dabco] is 25.9 and much higher than that of some familiar MOFs materials. Moreover, the composite Eu2O3@[Zn2(1,4-ndc)2dabco] can emit very intense characteristic fluorescence at 613 nm of Eu3t ion under ultraviolet radiation and can be used for detecting of fatty alcohols with different branch chains in fluorescence sensing because of its fluorescence intensity at 613 nm is sensitive to fatty alcohol with different carbon chains. The luminescence based sensing mechanism of the composite Eu2O3@[Zn2(1,4-ndc)2dabco] was discussed.
关键词： Flowing liquid,MOFs composites,Adsorption,Fatty alcohol with different branch chains,Pulsed laser ablation,Fluorescent sensing
更新于2025-09-23 15:19:57
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Self-assembled electrodes based on polyaniline grafted with reduced graphene oxide and polystyrene sulfonate
摘要： In this work, composites based on polyaniline (PAni) grafted with reduced graphene oxide (rGO) were obtained by the in situ chemical polymerization of aniline with rGO (mass ratio of 1 and 2.5%) dispersed into the monomer solutions. PAni and its PAni-rGO composites were used to prepare self-assembled (SA) films by depositing them onto indium tin oxide (ITO) substrates with alternating layers of polystyrene sulfonate (PSS). The structure and morphology of the materials were characterized by Fourier-transform infrared spectroscopy (FT-IR), RAMAN spectroscopy, and scanning electron microscopy (SEM). The oxidation states of PAni and its PAni-rGO composites were characterized by cyclic voltammetry (CV) and UV-Vis spectroscopy during the SA procedure. The electrochemical behavior of the obtained SA films was also characterized by electrochemical impedance spectroscopy (EIS). The EIS results showed a significant decrease in the polarization resistance (Rp), from 1020 to 302 Ω, for the film with 1% of rGO (PAni-1%rGO/PSS) when compared with its unmodified counterpart (PAni/PSS). The synergic effects observed for the PAni-1%rGO/PSS film showed that controlling the rGO mass ratio plays an important role in the improvement of the charge transfer processes, and that this electrode has potential for electrochemical applications, such as sensors and charge storage devices.
关键词： Conducting polymer composites,Polyaniline,Reduced graphene oxide,Self-assembly
更新于2025-09-23 15:19:57
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In-situ formation of ceramic layer on Mo-based composites via laser powder bed fusion
摘要： Poor oxidation resistance is a longstanding disadvantage of Mo-based materials for ultrahigh-temperature applications. In this study, we developed a facile strategy for depositing an in-situ ceramic layer on the surface of Mo-based composites via laser powder bed fusion (L-PBF) using Mo-based alloy powders covered with uniform Al2O3 nanoparticles and bridged by functionalized carbon nanotubes. The surface layer consisted of an α-Al2O3 matrix with a dispersed TiC phase and had a controllable thickness. The formation mechanism of this layer was investigated systematically through single-track observations and finite-element simulation. Moreover, the increased nanohardness can be attributed to the uniformly dispersed, intimately contacted ceramic nanoparticles in the matrix. The results indicated the multifunctionality of L-PBF-processed metallic parts, introducing the possibility of fabricating advanced ultrahigh-temperature materials.
关键词： carbon nanotubes,metal matrix composites,molybdenum,oxidation resistance,laser powder bed fusion
更新于2025-09-23 15:19:57
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A new electrochemically prepared composite counter electrode for dye-sensitized solar cells
摘要： In this paper, we propose new counter electrodes for applications in dye-sensitized solar cells (DSSCs). Polyaniline (PANi), tungsten trioxide (WO3), and their composite are deposited on indium thin oxide substrates using cyclic voltammetry technique and employed as counter electrodes that reached comparable and superior performances than Pt counter electrodes. These excellent results are achieved due to the high conductivity and electrocatalytic behavior of the prepared materials. Morphological, electrocatalytic, bonding structure, charge transfer properties, and photovoltaic characteristics are respectively investigated by field emission electron microscopy, cyclic voltammetry, Tafel analysis, Fourier-transform infrared spectroscopy, UV-visible spectroscopy, energy dispersive spectroscopy, electrochemical impedance spectroscopy, and current-voltage analysis. Our best DSSC that is fabricated from the WO3/PANi nanocomposite counter electrode demonstrated an efficiency of 6.78%, which is a 12.4% improvement in comparison with the Pt-based DSSC.
关键词： Counter electrode,Tungsten trioxide,Cyclic voltammetry,Composites,Dye-sensitized solar cells,Polyaniline
更新于2025-09-23 15:19:57
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Dielectric Measurements of Polymer Composite Based on CdS Quantum Dots in Low Density Polyethylene at Microwave Frequencies
摘要： CdS nanoparticles (NPs) as quantum dots (QDs) added into low density polyethylene (LDPE) can significantly change the MW dielectric properties of the composites. Introducing into the matrix of low density polyethylene CdS QDs increase the dielectric constant of more than twice. CdS QDs with concentration of 5 wt % to 20 wt % were prepared by the method of high-speed thermal decomposition. The size of CdS nanoparticles ranged from 2 nm to 7 nm. Experimental samples based on polymer-based nanocomposite in the form of thick films with a thickness of 80 to 100 microns were prepared by thermocompression. Complex dielectric permittivity of thick film samples was measured by T/R method from 2 to 8 GHz at room temperature (25°C). For samples with 20 wt % CdS NPs size effect was found. The change of dielectric properties of polymer composite materials is associated with the size of QDs. The dielectric constant and dielectric loss increases with decreasing size of the quantum dots. It is shown that the highest mean value of the dielectric constant and dielectric loss at a frequency range of 5 GHz to 8 GHz for cadmium sulfide nanoparticles with size of 4 nm were 12 and 189 dB/m, respectively. For QDs with ones of 6 nm average dielectric constant and dielectric loss were 5.8 and 134 dB/m, respectively. The effective dielectric constant and dielectric losses in the microwave range can be changed by CdS QDs of different sizes what consequently increases the possibility of using polymer nanocomposites as core elements of the microwave band-pass filters for various purposes.
关键词： quantum dot,cadmium sulfide,polymer composite,filled polymer,MW dielectric properties,low density polyethylene,composites
更新于2025-09-23 15:19:57
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Novel synthesis of Cu2CoSnS4-carbon quantum dots (CCTS:CQD) nano-composite potential light absorber for hybrid photovoltaics
摘要： A novel and simple synthesis of the absorber layer is indispensable in order to reduce the cost and processing of quantum solar cells. In this work, we developed novel Cu2CoSnS4-carbon quantum dot (CCTS:CQD) nano-composite as an absorbing material for solar cell applications. CCTS:CQD nano-composites were prepared by direct pyrolysis of CCTS precursors and citric acid. The proportions of citric acid precursor to CCTS were varied from 0.1 to 0.7. The properties of the synthesized nano-composite were studied using a UV-Vis spectrophotometer in the wavelength range of 300-900 nm. CCTS:CQD has a property of dynamic photoluminescence that depends on the excitation wavelength. The results of the X-ray diffraction revealed that the CCTS:CQD nano-composites were predominantly polycrystalline in nature. The formation of CCTS:CQD was confirmed by a high-resolution transmission electron microscope (HRTEM), which exhibits the size ~3 nm. The thin films of CCTS:CQD nano-composites were deposited on glass/ITO substrates by spray pyrolysis technique at 170 °C. Current-voltage (I-V) measurements carried out in dark and light conditions revealed CCTS:CQD thin films with good photo-response. The purpose of the present study is to develop CCTS:CQD nano-composite p-type absorber layer suitable for thin film solar cells.
关键词： quantum dot,photo-response,Thin Films,Nano-composites,Absorber
更新于2025-09-23 15:19:57