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Synthesis, characterization and photocatalytic activity of boron-doped titanium dioxide nanotubes
摘要： Two-step hydrothermal method was used to prepare undoped and boron-doped one-dimensional titanium dioxide (TiO2) nanotubes. Structural properties, thermal stability and microstructural features of the fabricated undoped titanium dioxide nanotubes (TNTs) and boron-doped titanium dioxide nanotubes (BTNTs) were characterized by Xeray diffraction, Raman, Fourieretransform infrared spectroscopy, nitrogen adsorption-desorption isotherms, scanning and transmission electron microscopy techniques. The photocatalytic activity of the fabricated nanotubes was evaluated by using methylene blue degradation. Boron addition to the titanium dioxide nanotubes up to 5% increased the photocatalytic methylene blue degradation ef?ciency. The achieved highest degradation ef?ciency was 81% and it was determined that higher (>5%) boron doped into the titanium dioxide nanotubes resulted in a decreased degradation ef?ciency.
关键词： Titanium dioxide nanotubes,Photocatalyst,Boron,Hydrothermal synthesis,Spectroscopy
更新于2025-09-04 15:30:14
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Nickel(II) Coordination Complex Constructed from Benzimidazole and Pyridine-2,6-dicarboxylate Co-ligands: Synthesis, Crystal Structure, Thermal Behavior, and Photoluminescence
摘要： A Ni(II) complex, [Ni(pydca)(bim)3] (pydca = pyridine-2,6-dicarboxylate, bim = benzimidazole) has been prepared by hydrothermal synthesis. It is characterized by elemental analysis, IR and thermal analysis. The crystal structure is determined by single crystal X-ray diffraction. The mononuclear complexes are linked by N–H···O hydrogen bonds. The title complex has good thermal stability and exhibits good fluorescence properties in ethanol solution at room temperature.
关键词： crystal structure,Nickel(II) complex,6-dicarboxylate,hydrothermal synthesis,benzimidazole,photoluminescence,thermal behavior,pyridine-2
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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Alkaline Hydrothermal Synthesis, Characterization, and Photocatalytic Activity of TiO <sub/>2</sub> Nanostructures: The Effect of Initial TiO <sub/>2</sub> Phase
摘要： One-dimensional (1D) titanate nanostructures were synthesized by hydrothermal route, using commercially available TiO2 (P25) and anatase powders as precursor materials and strong NaOH solution as catalyzer. The prepared titanates were calcined, followed by protonation to produce TiO2 nanostructures having enhanced photocatalytic and photovoltaic properties. The synthesized TiO2 1D nanostructures were characterized using field-emission scanning electron microscope, high-resolution electron microscope, X-ray diffraction analysis, and UV-Vis photospectroscopy to understand the effect of initial TiO2 phase on morphological and crystallographic features, and bandgap. Methylene blue degradation test was applied to evaluate the photoactivity of the products obtained after different stages of the process. The findings indicate that 1D TiO2 nanostructures form by different mechanisms from dissolved aggregates during hydrothermal process, depending on the crystal structure of the initial precursor used. Photocatalytic test results reveal that protonated titanates have considerable adsorption capability, while photocatalytic degradation depends on TiO2 transformation.
关键词： TiO2,Photocatalytic Activity,1D Structure,Hydrothermal Process,Nanoribbons
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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Facile synthesis, morphology and tunable photoluminescence properties of BaMgF <sub/>4</sub> :Ce <sup>3+</sup> /Tb <sup>3+</sup> /Eu <sup>3+</sup> phosphors
摘要： A series of BaMgF4:Ce3+/Tb3+/Eu3+ phosphors were successfully prepared via a facile hydrothermal process. X-ray diffraction (XRD), energy dispersive spectrometry (EDS), scanning electron microscopy (SEM), n-UV–UV-vis photoluminescence (PL) and fluorescence decays were employed to investigate the structure, composition, morphology, luminescence properties and energy transfer processes. The as-prepared BaMgF4 phosphors exhibit a rod-like morphology and the size of the product can be effectively regulated by changing the amount of NH4F in the original solution. Under n-UV–UV light excitation, the Ce3+, Tb3+ and Eu3+ singly-doped BaMgF4 phosphors all show good characteristic luminescence; the Ce3+–Tb3+ and Tb3+–Eu3+ co-doped BaMgF4 phosphors both show tunable emission colors from blue (green) to green (orange-red) because of the energy transfer of Ce3+ → Tb3+ and Tb3+ → Eu3+, respectively. Moreover, the efficient energy transfer from Ce3+ (Tb3+) to Tb3+ (Eu3+) ions in the co-doped samples was confirmed by investigating the excitation/emission spectra and decay lifetimes. The results indicate that the phosphors may be potentially used as single-component multi-color phosphors for white light-emitting diodes.
关键词： energy transfer,BaMgF4,white light-emitting diodes,phosphors,hydrothermal process
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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Ultra-small amorphous carbon dots: preparation, photoluminescence properties, and their application as TiO2 photosensitizers
摘要： Ultra-small carbon quantum dots (s-CQDs) with excitation wavelength-independent fluorescence had been obtained by hydrothermal-followed acid precipitation method and were characterized by FT-IR, TEM, XPS, UV–Vis and XRD. It was found that as-prepared s-CQDs were amorphous spherical particles with an average diameter of 1.51 nm, and there were abundant hydroxyl and carbonyl groups on their surfaces. Moreover, fluorescence emission study found that the luminescence of s-CQDs was aroused by oxygen group decorated on its surface, and the fluorescence properties of s-CQDs were much different from those of large CQDs (l-CQDs), which showed higher quantum yield and better photoluminescence (PL) property than that of l-CQDs. The PL of s-CQDs possessed two emission centers and was exhibited to be excitation independent. When s-CQDs was used as photosensitizer for TiO2 to photocatalytic degradation of methylene blue under visible light irradiation, it showed significantly improved photocatalytic activities compared with 1-CQDs, and the degradation efficiency of methylene blue reached up to 96.6%. The high degradation efficiency was attributed to the ultra-small particle size, abundant acidic groups, and excellent optical properties of s-CQDs.
关键词： Photocatalytic degradation,Ultra-small carbon quantum dots,TiO2 photosensitizers,Photoluminescence,Hydrothermal-followed acid precipitation method
更新于2025-09-04 15:30:14
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Hydrothermal synthesis of flower-like Na-doped α-Bi2O3 and improved photocatalytic activity via the induced oxygen vacancies
摘要： Na-doped α-Bi2O3 with a hierarchical flower-like shape was successfully prepared via a facile hydrothermal reaction. The samples consisted of well-crystalized nanoplates with smooth surfaces and a thickness of tens of nanometers. The phase formation was investigated via X-ray powder diffraction (XRD) patterns and structural refinements. The formations of oxygen vacancies were verified and its effects on the optical and photocatalysis were discussed. The band gap of α-Bi2O3 was narrowed via forming the local energy levels by oxygen vacancy defect complexes in the lattices. The photocatalytic activities on photo-degradation of Rhodamine B (RhB) were significantly improved. The effective photocatalysis was discussed on the improved visible-light response, band structure, and dynamic luminescence decay. The photocatalysis of Na-doped α-Bi2O3 was improved via the induced oxygen vacancies. The reported hydrothermal synthesis was advantageous approach to prepare α-Bi2O3 by considering the simplicity, low reaction temperature, no post-sintering, without using any template or surfactant, large-scale production, low cost, etc.
关键词： Photocatalysis,Semiconductor,Hydrothermal synthesis,Optical properties,Oxygen vacancies
更新于2025-09-04 15:30:14