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One-pot synthesis of cubic ZnSnO3/ZnO heterostructure composite and enhanced gas-sensing performance
摘要： In this work, we have successfully prepared cubic ZnSnO3/ZnO heterostructure composite (CZS/ZO) by a one-pot hydrothermal method. This composite easily forms a hollow structure through an alkali etching process while keeping its shape unchanged. The possible growth mechanisms have been studied and the material proves to have excellent gas sensing properties. The response of hollow cubic ZnSnO3/ZnO NPs (HZS/ZO) is up to 101 in 50 ppm triethylamine (TEA) gas at a working temperature of 160 (cid:1)C; the lower limit of detection is 1 ppm. Moreover, the materials exhibit high selectivity and good stability. The role of ZnSnO3/ZnO n-n heterojunction in enhancing gas sensitivity is discussed.
关键词： Heterostructure composite,Triethylamine,Hollow cubic ZnSnO3/ZnO,Gas-sensor
更新于2025-09-10 09:29:36
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The synthesis of Bi2S3/2D-Bi2WO6 composite materials with enhanced photocatalytic activities
摘要： Bi2S3/2D-Bi2WO6 composite materials which combined 2D-Bi2WO6 with Bi2S3 nanoparticles were prepared via ion exchange method. The mass ratio of Bi2S3 nanoparticle could be modulated by changing the quantity of thioacetamide (TAA). For Bi2S3/2D-Bi2WO6 composite materials, Bi2S3 nanoparticles dispersed on the surface of Bi2WO6 nanosheets. The photocatalytic activity was evaluated by photodegradation rhodamine B (RhB) under visible light. RhB was photodegraded nearly completely by BWS-2, while only 67% was photodegraded by Bi2WO6 nanosheet after 5 hours’ visible light irradiation. Based on the optical and electrochemical measurements, Bi2S3/2D-Bi2WO6 composite materials have prolonged carriers’ lifetime, improved carriers’ separation efficiency and decreased carriers’ recombination efficiency. These results endow Bi2S3/2D-Bi2WO6 composite materials with high photocatalytic activities.
关键词： Bi2S3/2D-Bi2WO6,ion exchange method,photocatalytic activities,visible light,composite materials
更新于2025-09-10 09:29:36
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Effect of Heat Treatment on The Crystal Structur, Electrical Conductivity and Surface of Ba <sub/>1.5</sub> Sr <sub/>0.5</sub> Fe <sub/>2</sub> O <sub/>5</sub> Composite
摘要： The Composite of Ba1,5Sr0,5Fe2O5 has been synthesized by using powder metallurgy technique. The Ba1.5Sr0.5Fe2O5 were prepared from BaCO3, SrCO3 and Fe2O3 raw materials with a specific weight ratio. The three materials were synthesized by powder metallurgy under heat treatment at 800 °C, 900 °C, and 1000 °C for 5 hours. All the three samples were characterized by using X-ray Diffraction (XRD) to determine the crystal structure and crystal size, LCR meter to determine the conductivity, and Scanning Electron Microscope (SEM) to observe the morphological of the composites. The phase analysis result showed that the composite consists of several minor phases such as BaO2, SrO2, and Fe2O3. The Crystal size of composite Ba1.5Sr0.5Fe2O5 decreased while increases the strain of crystal with increasing of sintering temperature. The crystal size of the Ba1.5Sr0.5Fe2O5 composite is 3.55 nm to 7.23 nm and value of strain is 8.47% until 3.90%. Based on the conductivity measurement, it was obtained that the conductivity of the Ba1.5Sr0.5Fe2O5 composite decreased with increasing sintering temperature. It was also noticed that the conductivity increased with increasing of frequency. The conductivity ranged from 6.619?10-7 S/cm to 65.659?10-7 S/cm. The energy dispersive spectroscopy (EDS) analysis showed that several dominant elements were a good agreement with the phase analysis.
关键词： surface,Ba1.5Sr0.5Fe2O5,conductivity,Composite,X-ray diffraction
更新于2025-09-10 09:29:36
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Novel luminescent PLA/MgAl2O4:Sm3+ composite filaments for 3D printing application
摘要： In this work, luminescent bioplastic composite ?laments for 3D printing were fabricated from polylactic acid (PLA) and samarium doped magnesium aluminate phosphor (MgAl2O4:Sm3+). The phosphor was prepared by a metal-complex decomposition method. The obtained powder was then modi?ed by 3-aminopropyl triethoxysilane to improve compatibility with PLA matrix. Untreated and treated phosphors exhibited characteristic photoluminescent (PL) peaks of Sm3+ ion. Composite ?laments of PLA with different amounts of phosphors (0, 1, 2, 3 and 4 phr) were produced by an extrusion process. Differential scanning calorimetry (DSC) scans have revealed that the phosphor ?llers lowered glass-transition (Tg), crystallization (Tc), and melting (Tm) temperatures of the PLA. PL measurements have shown luminescent properties of 3D printed samples resembling those of phosphor powders. Luminescent intensity was increased with the increasing ratio of phosphors. The phosphors not only developed luminescence but also strengthened mechanical properties of the composites. Furthermore, surface modi?cation was able to improve the mechanical properties of the composite ?laments as evident in a series of mechanical tests.
关键词： Polymer composite,3D printing,Samarium doped magnesium aluminate,Polylactic acid,Phosphor
更新于2025-09-10 09:29:36
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Applications of sunlight responsive Fe-Ag-TiO2 composite incorporating in-situ dual effect for the degradation of pentoxifylline
摘要： Silver modified TiO2 based immobilized system incorporating in-situ dual effect (photocatalysis and photo-Fenton) was examined for the degradation and mineralization of an environmentally persistent drug, pentoxifylline (PEN) under natural sunlight. The modified TiO2 was characterized through DRS, XRD, SEM/EDS, TGA, XPS, FTIR, and Raman spectroscopy to confirm the distribution of Ag on TiO2 surface. Ag-TiO2-P25 exhibited better degradation efficiency with high rate constant i.e. 0.055 min?1 in comparison to 0.037 min?1 (unmodified TiO2-P25). Attempts were made to enhance the degradation efficiency of system by incorporating in-situ dual effect in fixed-mode using Ag-TiO2-P25. Novel clay beads using waste fly-ash and foundry sand were used for Ag-TiO2-P25 immobilization (Fe-Ag-TiO2 composite). The value of rate constant was augmented to 0.132 min?1 with dual process. The practical feasibility of technique was validated by conducting the degradation of PEN in a solar pilot-scale reactor with total volume handling of 5 L using Fe-Ag-TiO2 composite.
关键词： Clay beads,Dual effect,Ag-TiO2-P25,Fe-Ag-TiO2 composite
更新于2025-09-10 09:29:36
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DUAL-BAND COMPOSITE WIDEBAND ABSORBING MATERIAL FOR BROADBAND ANTENNA IN-BAND RADAR CROSS SECTION REDUCTION
摘要： A composite wideband absorbing material (WAM) covering dual bands is designed, to reduce the in-band radar cross section (RCS) for broadband antenna in this paper. The upper layer is a traditional absorber while the lower one is a dual-band frequency selective surface (FSS), which is formed by a square ring and an improved Jerusalem cross structure. The absorbing band has been broadened to 112% compared with the magnetic sheet without FSS. Over C and X bands, the absorption rate is over 90%. By using the FSS-based WAM as the ground plane of a Vivaldi antenna, substantial RCS reduction is obtained from 2–18 GHz. Moreover, the RCS is reduced remarkably over ?80?–80? incident angles except for minority angles, with the radiation performance preserved at the same time. The experimental results are in good agreement with the simulated ones.
关键词： Vivaldi antenna,frequency selective surface,radar cross section reduction,dual-band,composite wideband absorbing material
更新于2025-09-10 09:29:36
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Multiple charge carrier transfer pathways in BiOBr/Bi2O3/BiO0.67F1.66 ternary composite with high adsorption and photocatalytic performance
摘要： BiOBr/Bi2O3/BiO0.67F1.66 ternary composites were designed and prepared via a facile chemical precipitation method and their photocatalytic performances were assessed by degradation of rhodamine B (RhB) under visible light illumination. The highest activity was achieved over BiOBr/Bi2O3/BiO0.67F1.66 ternary composite with Br/F molar ratio of 1:1, which approximately degraded 98.61% of RhB after just 15min irradiation. Contrast to pure BiOBr, the enhanced photocatalytic performances of the ternary composites could be attributed to their larger specific surface areas and multiple charge carrier transfer pathways, which efficiently promoted separation of charge carriers. Besides, the formation mechanism of the composites was discussed in detail as well.
关键词： Bi2O3,Charge carrier transfer pathway,BiOBr,Ternary composite,BiO0.67F1.66
更新于2025-09-10 09:29:36
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Carbon Nanotubes - Current Progress of their Polymer Composites || Carbon Nanotube-Conducting Polymer Composites as Electrode Material in Electroanalytical Applications
摘要： This chapter gives a brief overview of the preparation, characterization, and analytical applications for combinations of polymers and carbon nanotubes (CNTs) that have been prepared in different ways, which are used as an electrode material. For this purpose, multiwalled or single-walled CNTs are composed of different types of conductive polymers. The preparation of CNT-conducting polymer composite electrodes was explained by their deposition order. Chemical and morphological surface characteriza‐ tions of composite electrodes were presented by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. In addition, CNT-based polymer composite electrode usage in sensor applications for trace organic/inorganic compounds and energy applications is discussed in the last part of this chapter.
关键词： composite electrodes,conducting polymers,electron microscopy,Carbon nanotubes,metal nanoparticels scanning
更新于2025-09-10 09:29:36
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Laser cladding composite coating on mild steel using Ni–Cr–Ti–B <sub/>4</sub> C powder
摘要： The composite coating was fabricated by laser cladding on Q235 mild steel. The cross-section morphology, microstructure, phase, micro-hardness and wear resistance of the coating were investigated by scanning electron microscope, energy dispersive spectrometry, X-ray diffraction, Vickers micro-hardness tester and dry sliding wear testing machine, respectively. Results showed that composite coating was gained without cracks and bonded with substrate excellently because of the prominent metallurgical bonding. The composite coating was made up of Ni3Ti, Cr2Ti, Ni–Cr–Fe, TiB2 and TiC. Ceramic reinforcements existed in coating with eutectic and independent structures. The micro-hardness of coating was about 5 times the substrate. Compared with substrate, the coating showed superior wear resistance.
关键词： laser cladding,wear resistance,microstructure,Q235 mild steel,Composite coating
更新于2025-09-10 09:29:36
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Calcination effect to the physical and optical properties of Zn <sub/>2</sub> SiO <sub/>4</sub> composite prepared by impregnation of ZnO on SiO <sub/>2</sub> amorphous nanoparticles
摘要： In this study, Zn2SiO4 composite-based ceramic was synthesised using amorphous SiO2 nanoparticles as a silicon source. The amorphous SiO2 nanoparticles which obtained from a simple precipitation process were mixed with aqueous zinc nitrate. Amorphous SiO2 nanoparticles were encapsulated by the zinc source in aqueous solution, dried, and subjected to calcination. The underwent calcination showed the changing of phases, morphology, and size with increased temperatures. During calcination, ZnO phase appeared at the beginning of heating temperature and Zn2SiO4 phase started to emerge at 800 °C onwards, as shown by XRD patterns. The optical band gap analysis of Zn2SiO4 composite was determined to be within the range of 3.12 to 3.19 eV. The diffusion of zinc ions into SiO2 nanoparticles with high surface area also reduced the phase formation temperature for Zn2SiO4, compared to a conventional solid state method. This optical characteristic is expected to be a potential candidate for phosphor materials in opto-electronic devices application.
关键词： optical properties,Zn2SiO4 composite,amorphous SiO2 nanoparticles,phosphor materials,calcination
更新于2025-09-10 09:29:36