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Structural Modification, Synthesis Mechanism and Properties Analysis of Li4Ti5O12 Anode Materials
摘要： Li4Ti5O12 microsphere was synthesized by hydrothermal method. The effects of amount of lithium hydroxide, hydrothermal time and sintering temperature on properties of sample were studied. The synthesis mechanism of Li4Ti5O12 microsphere was preliminary analyzed. The structural characterization was analyzed by X-ray diffraction, and the morphology was investigated by scanning electron microscopy and transmission electron microscopy. The properties of galvanostatic charge, discharge and cycle stability were also studied. The results indicated that when 2.55 mmol LiOH?H2O reacted with 0.2 g hydrolysate, the sample had pure phase, when the hydrothermal condition was 36 h and 180 oC, the structure of sample particle was intactly spherical. The volume average size of samples were between 400 nm to 600 nm. The charge and discharge voltage plateau of samples were very stable. When the sintering temperature was 700 oC, the first discharge capacity was 148.3 mAh?g-1 at 0.1 C. After 10th cycle, the discharge capacity retained at 132.5 mAh?g-1.
关键词： hydrothermal method,electrochemical property,hydrothermal condition,Lithium titanate
更新于2025-09-04 15:30:14
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Photoluminescence and Growth Mechanism of Oriented Hierarchical Fibrous-Like ZnO Nanowires
摘要： Oriented hierarchical fibrous-like ZnO nanowires with the diameter of about 30–50 nm and the length of about 15–30 um were successfully synthesized on the seed-coated Zn substrates by a simple two-step process. The morphology and structure of the obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It is shown that fibrous-like ZnO nanowires with the aspect ratio of about 500～1000 present the dense reticular structure, which are grown on ZnO nanowire arrays. But beyond that, as-prepared samples are found to be good single crystalline with hexagonal wurtzite structure and preferential grow along the c-axis. A possible growth mechanism of oriented hierarchical fibrous-like ZnO nanowires is presented in detail, revealing that the synthesis of fibrous-like ZnO nanowires should be attributed to differences in the growth rate of the different crystallographic planes and the two growth ways. The photoluminescence (PL) spectra of oriented hierarchical fibrous-like ZnO nanowires grown at 240 min shows the 5 nm blue-shift and enhanced intensity property in the UV emission.
关键词： Hydrothermal Method,Fibrous-Like ZnO Nanowires,Formation Mechanism,Oriented Hierarchical,PL Property
更新于2025-09-04 15:30:14
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Synthesis of Si-based KH560/RGO@Fe3O4 composite for improving electromagnetic properties in 2–18?GHz frequency range
摘要： Silicon coupling reagent is regarded as a common additive on surface treatment of polymer due to its high bonding strength and low cost. In this paper, a series of γ-(2, 3-epoxypropoxy) propyltrimethoxysilane (KH560)-based reduced graphene oxide (RGO)@Fe3O4 (KH560/RGO@Fe3O4) composites with different ratio of Fe3O4 nanoparticles (NPs) are synthesized by a facile hydrothermal method. It is confirmed that the silicon reagent KH560, as a hopeful candidate for increasing the RGO lattice defects, is favorable to improve the electromagnetic wave absorption. Meanwhile, the microwave attenuation mechanism of KH560/RGO@Fe3O4 composite suggests that the dielectric loss mainly causes by multiple Debye dipolar relaxation and its magnetic loss comes from the eddy-current effect of Fe3O4 NPs over the high frequency range. In consequence, the KH560/RGO@Fe3O4 composite endows the excellent absorption performance, the reflection loss (RL) value is optimized to ? 25 dB at 14.1 GHz with a thickness of 3 mm and the maximum frequency bandwidth for RL < ? 10 dB is 4.1 GHz with a thickness of 4 mm.
关键词： Electromagnetic wave absorption,Fe3O4 nanoparticles,Reduced graphene oxide,Hydrothermal method,Silicon coupling reagent
更新于2025-09-04 15:30:14
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Construction of Ti3+ self-doped TiO2/BCN heterojunction with enhanced photoelectrochemical performance for water splitting
摘要： Ti3+ self-doped TiO2/BCN heterojunction (Ti3+-TiO2/BCN) was constructed via a hydrothermal method with using NaBH4 as reducing agent. The BCN nanosheets function as a good support to block the agglomeration of Ti3+-TiO2 nanoparticles, which decreased the recombination of photogenerated charge carriers. The Ti3+-TiO2/BCN sample exhibited enhanced electronic conductivity and absorption in visible light region because of the introduction of Ti3+ and oxygen vacancies (Ov). The as-prepared Ti3+-TiO2/BCN sample showed enhanced photoelectrochemical (PEC) performance as confirmed by analyses of LSV, EIS, Bode plots and M–S. Under the visible light irradiation, the optimally Ti3+ self-doped TiO2/BCN heterojunction sample yield a photocurrent density of ～ 0.69 mA/cm2 at 1.23 V versus RHE, which is over three times as high as BCN and TiO2/BCN at the same conditions.
关键词： hydrothermal method,photoelectrochemical performance,NaBH4,water splitting,Ti3+ self-doped TiO2/BCN heterojunction
更新于2025-09-04 15:30:14
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Luminescence properties of Tb <sup>3+</sup> doped Gd <sub/>2</sub> (WO <sub/>4</sub> ) <sub/>3</sub> phosphor prepared by hydrothermal method
摘要： The Gd2(WO4)3:Tb3+ phosphors have been successfully prepared using the hydrothermal method calcined at 900℃ in this work. The crystal structure, PLE/PL and fluorescence decay behavior of samples were investigated in detail. Under the 270 nm excitation (4f8→4f75d1 transition of Tb3+), the (Gd2-xTbx)(WO4)3 (x=0.01-0.15) phosphors emit the strong green emission at 547 nm (5D4→7F5 transition of Tb3+). The quenching concentration was found to be ~10% owing to the exchange reaction between Tb3+. The Tb3+ addition did not influence the CIE chromaticity coordinates (~0.33±0.02, ~0.60±0.02) and color temperatures (~5542 K) of the (Gd2-xTbx)(WO4)3 phosphors. However, due to the energy transfer between Tb3+, the fluorescence lifetime for 547 nm emission decreased with the Tb3+ content increasing. The Gd2(WO4)3:Tb3+ phosphors with strong green emission are expected to be widely used in white light LED and display areas.
关键词： Tb3+ doped,Gd2(WO4)3 phosphor,hydrothermal method,Luminescence,green emission
更新于2025-09-04 15:30:14
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Synthesis of Mesoporous Molybdenum Disulfide (MoS <sub/>2</sub> ): A Photocatalyst for Removal of Methylene Blue
摘要： Mesoporous molybdenum disulfide (MoS2) nanostructures were synthesized successfully by hydrothermal method. Their physicochemical properties were studied by X-ray diffraction analysis, scanning electron microscopy and Brunauer–Emmett–Teller surface area analysis. These nanostructures were used as adsorbent and heterogeneous nanocatalyst for removal of methylene blue (MB) as an environmental pollutant organic dye. MoS2 mesoporous nanostructure showed excellent activity for removal of methylene blue under visible light at room temperature. The removal yields of methylene blue by mesoporous nanostructure was 99.6% in 15 minutes which is high enough in comparison with bulk MoS2.
关键词： Methylene Blue,Photocatalyst,Molybdenum Sulfide,Hydrothermal Method,Mesoporous,Heterogeneous Nanocatalyst
更新于2025-09-04 15:30:14
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Structural and optical properties of highly thermally active Gd2Zr2O7:Dy3+ phosphors for lighting applications
摘要： Near white light emitting (Gd2?2x Dy2x Zr2O7) (2x = 0.01, 0.02, 0.04, 0.06, 0.08) phosphors have been synthesized by the facile hydrothermal method. To examine the structural and optical properties, the prepared phosphors were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), photoluminescence spectroscopy (PL) and UV–Vis diffuse reflectance spectroscopy. The XRD results confirm the defect fluorite structure of the prepared phosphors having cubic crystal system with space group Fm3m and incorporation of Dy3+ ions does not modify host lattice crystal structure. The photoluminescence properties have been well studied in respect of excitation spectra, emission spectra and decay kinetics. The PL emission spectra of the sample under 351 nm UV excitation exhibits two intense peaks around 484 nm and 580 nm which are attributed to the transitions 4F9/2–6H15/2 and 4F9/2–6H13/2, respectively of Dy3+ ion. The emission intensity goes on increasing until Dy3+ doping concentration reaches at 2 mol% and intensity decreases thereafter on higher concentration. The average life times are found to decrease with the increase of Dy3+ concentration. Photometric studies such as CIE color coordinate, CCT and Color purity facilitate that the reported phosphors can generate near white light emission. Temperature dependent PL spectral measurement reveals that the emission intensity as well as the life time gradually increases with temperature. Thus, the affirmative experimental result indicates that the Dy3+ ions doped Gd2Zr2O7 phosphors can be used as active near white lighting emitting phosphor materials.
关键词： white light emitting diode,Gd2Zr2O7:Dy3+,photoluminescence,phosphors,hydrothermal method
更新于2025-09-04 15:30:14
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Three Cadmium Tartratoborates with Good Second Harmonic Generation (SHG) or Luminescence Performances
摘要： Three new cadmium(II) tartratoborates, namely, Cd5[(C4H2O6)2B]2(H2O)8·3H2O (1), K2Cd4[(C4H2O6)2B]2(H2O)2 (2), and Li0.92K1.08Cd1.5[(C4H2O6)2B](H2O)2 (3), have been successfully synthesized by the hydrothermal method. Compounds 1?3 belong to centric C2/c, acentric Pc, and the polar C2, respectively. Through based on the same hybrid borate?tartrate [(C4H2O6)2B]5? anions, they exhibit different structures. The [(C4H2O6)2B]5? anion is composed of two tartrate anions and a B(OH)4? unit. Compound 1 features a novel 2D {Cd3[(C4H2O6)2B]2(H2O)2}4? anionic layers and [Cd2O10] dimers, forming tunnels of large 14-MRs which are filled by the non-coordination water molecules. Compound 2 has a characteristic 3D network based on {Cd2[(C4H2O6)2B]}? units interlinked via carboxylate groups, forming tunnels of 11-MRs, half of which stuffed with the K+ ions. Compound 3 features 2D {Cd4[(C4H2O6)4B]}3+ layers which are separated by K/Li ions. Luminescent studies suggest that they emit blue light. Compounds 2 and 3 display phase-matchable second harmonic generation signs of about 3.2× and 1.5× KH2PO4, respectively.
关键词： luminescence,hydrothermal method,cadmium tartratoborates,second harmonic generation
更新于2025-09-04 15:30:14
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Structural and luminescence properties of Eu3+ doped LaAlO3 nanophosphors by hydrothermal method
摘要： A series of La1?xAlO3: xEu3+ (x = 0, 2, 4, 6 and 8 mol%) nanophosphors have been synthesized by a hydrothermal technique and were investigated by an X-ray powder diffractometer, field emission scanning electron microscopy, high-resolution transmission electron microscopy and fourier transform infrared spectroscopy. Further, photoluminescent studies have also been orderly explored under the near-ultraviolet light excitation. When excited with 395 nm, the Eu3+: LaAlO3 nanophosphors emission peaks observed at 579, 591, 620, 649 and 700 nm due to the 5D0→7Fj (J = 0–4) transitions of Eu3+ ions. The prominent emission peak was perceived at 620 nm, which associated to the 5D0→7F2 hypersensitive transition of Eu3+ ion. The optimum doping concentration of Eu3+ in LaAlO3 host is around 6 mol% and the concentration quenching effect is through the dipole–dipole interaction. The Commission International de I’Eclairage (CIE) color co-ordinates were determined from emission spectra and the values (x, y) were closer to National Television Standard Committee typical value of red emission. As an outcome, the prepared nanophosphors are highly suitable for red component of white light emitting devices.
关键词： white LEDs,nanophosphors,hydrothermal method,photoluminescence,LaAlO3:Eu3+
更新于2025-09-04 15:30:14
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Facile synthesis of Ag/ZnO metal–semiconductor hierarchical photocatalyst nanostructures <i>via</i> the galvanic-potential-enhanced hydrothermal method
摘要： Hierarchical metal–semiconductor nanostructures (NSs) composed of a backbone made of Ag nanowire and ZnO nanorod (NR) branches were successfully prepared using the galvanic-potential-enhanced hydrothermal method. A galvanic cell structure was formed between an Al bottle anode that was used as a hydrothermal reactor and an Ag NW cathode dispersed in a hydrothermal solution. As a result, the contact-potential-driven hydrothermal growth of the ZnO NRs on the sidewalls of the Ag NWs could be achieved. The morphological and microstructure characterization confirmed the formation of well-arranged hierarchical NSs composed of Ag NW trunk and ZnO NR branch structures. The photocatalytic properties of the hierarchical Ag/ZnO NSs were investigated by degrading methylene blue (MB) dye as a model pollutant. It was found that the hierarchical Ag/ZnO NSs demonstrated a more than two-fold faster degradation rate than the pristine ZnO NSs. The high-performance photocatalytic activity of the Ag/ZnO hierarchical NSs was attributed to the synergetic effect of the metallic Ag NWs and the ZnO NRs that enhanced the charge separation and diffusion by suppressing charge recombination, as well as enhanced reaction sites and light absorption.
关键词： methylene blue degradation,Ag/ZnO,photocatalytic activity,hierarchical nanostructures,galvanic-potential-enhanced hydrothermal method
更新于2025-09-04 15:30:14