scholarly journals Strong Visible Absorption and Photoluminescence of Titanic Acid Nanotubes by Hydrothermal Method

2008 ◽  
Vol 112 (14) ◽  
pp. 5361-5364 ◽  
Author(s):  
B. L. Tian ◽  
X. T. Zhang ◽  
S. X. Dai ◽  
K. Cheng ◽  
Z. S. Jin ◽  
...  
Keyword(s):  
Hydrothermal Method ◽  
Visible Absorption ◽  
Titanic Acid Nanotubes

TiO2 Nanoparticles Synthesized with Ti(SO4)2 as Precursor via the Hydrothermal Method and their Optical Absorption Properties

2017 ◽  
Vol 727 ◽  
pp. 280-283
Author(s):  
Xiao Ming Fu
Keyword(s):  
Hydrothermal Method ◽  
Ph Value ◽  
Blue Shift ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Absorption Properties ◽  
Tem Analysis ◽  
Visible Absorption ◽  
Transmission Electron ◽  
20 Nm

Anatase TiO2 particles of about 20 nm in the diameter were successfully synthesized with Ti (SO4)2 as titanium source and stronger ammonia water as precipitant at 240°C for 48 h with pH=5 using the hydrothermal method. The samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and ultraviolet-visible absorption spectroscopy (UV-VIS). XRD analysis showed that the phase of the samples was anatase TiO2. TEM analysis confirmed that TiO2 particles of about 50 nm in the diameter were obtained when the pH value was 0.12. With the increasement of the pH value, the size of as-prepared TiO2 particles became remarkably fine. However, with the further increase of the pH value, the size of TiO2 particles was not obvious. TiO2 particles of about 20 nm in the diameter were obtained when the pH value was 5. And UV-VIS results showed that the size of anatase TiO2 nanoparticles, which became small, was propitious to the blue shift of their absorption peak.

Synthesis of High-Performance Aqueous CdSe Quantum Dots Based on Combination of Se Source as Vapor-Phase and Hydrothermal Method

2010 ◽  
Vol 663-665 ◽  
pp. 96-99
Author(s):  
Heng Kang Qiu ◽  
Yue Shen ◽  
Lin Jun Wang ◽  
Jian Cheng Zhang ◽  
Kai Feng Qin
Keyword(s):  
Quantum Dots ◽  
Hydrothermal Method ◽  
Vapor Phase ◽  
High Performance ◽  
Hydrothermal Reaction ◽  
Water Soluble ◽  
Quantum Yields ◽  
Cdse Quantum Dots ◽  
Cdse Qds ◽  
Visible Absorption

High performance aqueous CdSe quantum dots (QDs) have been prepared by combination of Se source as vapor-phase and hydrothermal method. The main advantages of this approach included: one is to utilize H2Se vapor as a higher pure selenium source to make the prepared QDs have little other impurities, another is to obtain the QDs with characteristics of more rapid growth in the hydrothermal reaction. The as-prepared products have been characterized by ultraviolet-visible absorption spectra, photoluminescence spectroscopy (PL), X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and energy dispersive spectroscopy (EDS) analysis etc. The results show the as-synthesized water-soluble CdSe nanoparticles possess higher purity and quantum yields (QY), favorable narrow photoluminescence band with full width of half-maximum (FWHM) down to 40 nm, better photo-stability, and less synthetic time as compared with aqueous CdSe QDs obtained by other methods.

Synthesis and Characterization of Nickel Oxide Nanostructures by Hydrothermal Method

2018 ◽  
Vol 24 (8) ◽  
pp. 5691-5694 ◽  
Author(s):  
D Sathisha ◽  
K. Gopalakrishna Naik
Keyword(s):  
Nickel Oxide ◽  
Hydrothermal Method ◽  
Optical Band Gap ◽  
Volume Ratio ◽  
Band Gap Energy ◽  
Visible Absorption ◽  
Oxide Nanostructures ◽  
Water As Solvent ◽  
Uv Visible

Nickel oxide (NiO) nanostructures were synthesized by hydrothermal method using ethylene glycol and double distilled water as solvent in 3:2 volume ratio. The synthesized nanostructures were characterized by XRD, FESEM, EDX, FTIR, and UV-visible spectroscopy. XRD result shows that the synthesized nanostructures are polycrystalline in nature. FESEM images show the growth of NiO nanowires. The elemental compositions of the samples were analyzed by EDS. Fourier transform infrared (FTIR) spectroscopy confirms the existence of Ni–O bond in the sample. Optical band gap energy of about 3.71 eV was calculated from the UV-visible absorption measurement.

Uniform Nano/Micron-Sized ZnO Spheres with Controllable Diameter

2012 ◽  
Vol 496 ◽  
pp. 268-271
Author(s):  
Ji Hang Cheng ◽  
Shuang Xu ◽  
Chang Hong Ding
Keyword(s):  
Hydrothermal Method ◽  
Absorption Spectra ◽  
Volume Ratio ◽  
Average Diameter ◽  
Absorption Peak ◽  
Nano Particles ◽  
Visible Absorption ◽  
Uv Visible

Novel uniform nano/micron-sized ZnO spheres assembled from the aggregation of nano-particles have been synthesized by hydrothermal method. It was observed that ZnO spheres with controllable diameter were obtained when various volume ratios of triethanolamine (TEA) to H2O were used. Increasing the volume ratio of TEA to H2O could result in the formation of loosely packed ZnO spheres. The UV-visible absorption spectra show that the absorption peak red-shifts with the increasing average diameter of the spheres.

Synthesis of CuO Microspheres by the Simple Hydrothermal Method and their Optical Absorption Properties

2012 ◽  
Vol 562-564 ◽  
pp. 490-493
Author(s):  
Xiao Ming Fu
Keyword(s):  
Optical Absorption ◽  
Hydrothermal Method ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
Absorption Properties ◽  
Visible Absorption ◽  
X Ray ◽  
Cuo Microspheres ◽  
Visible Absorption Spectroscopy

CuO microspheres with a diameter range of 1~3 μm are successfully synthesized with 1 m mol CuCl2 as copper source and 3 m mol Na2CO3 as auxiliary salt at 180 °C for 24 h via the easy hydrothermal method. The phase, the morphologies and optical absorption properties of the samples have been characterized and analyzed by XRD (X-ray diffraction), SEM (Scanning electron microscope) and ultraviolet-visible absorption spectroscopy (UV-VIS), respectively. XRD analysis shows that the phase of as obtained samples is CuO. SEM analysis confirms that the increase of the the auxiliary salt is in favor of the synthesis of CuO microrods. And UV-VIS measurements show that CuO microspheres have a good optical absorption property.

scholarly journals Effect of PdS on Photocatalytic Hydrogen Evolution of Nanostructured CdS under Visible Light Irradiation

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Qingyun Chen ◽  
Cheng Suo ◽  
Shu Zhang ◽  
Yunhai Wang
Keyword(s):  
Visible Light ◽  
Hydrothermal Method ◽  
Hydrogen Evolution ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Visible Absorption ◽  
Photocatalytic Hydrogen Evolution ◽  
Transmission Electron ◽  
Highly Dispersed

To investigate the effect of PdS as a cocatalyst for photocatalytic hydrogen evolution, nanostructured PdS/CdS were prepared by an in situ coprecipitation and hydrothermal method, respectively. The as-prepared photocatalysts were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-visible absorption spectra, and photoluminescence spectra (PL). With PdS highly dispersed in the CdS nanostructures, the photoactivity was evaluated by hydrogen evolution from aqueous solution containing Na2S/Na2SO3as sacrificial reagents under visible light irradiation. When the concentration of PdS was 1% by weight, PdS/CdS, prepared by the in situ coprecipitation, showed the highest photocatalytic activity, while that prepared by hydrothermal method showed the most stability for hydrogen evolution. The effect of highly dispersed PdS on the photoactivity was discussed.

Preparation of ZnSe Quantum Dots by Hydrothermal Method Assisted by Ammonia

2019 ◽  
Vol 956 ◽  
pp. 99-106
Author(s):  
Hui Kai Han ◽  
Jin Cheng Huang ◽  
Hang Qi ◽  
Du You Lu
Keyword(s):  
Quantum Dots ◽  
Reaction Time ◽  
Optimal Condition ◽  
Hydrothermal Method ◽  
X Ray Diffraction ◽  
Ligand Effect ◽  
Visible Absorption ◽  
Transmission Electron ◽  
Uv Visible ◽  
Defect Luminescence

ZnSe quantum dots (QDs) with high intrinsic fluorescence quantum efficiency (QY) and low defect luminescence were prepared by hydrothermal method assisted with ammonia, in which the selenium powder and zinc acetate were used as Se and Zn source, and the mercaptopropionic acid (MPA) was used as ligand. Effect of ammonia amount, Zn/Se ratio, Zn/MPA ratio, and reaction time was investigated in detail in this study. The as-prepared ZnSe QDs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-visible absorption spectrum (UV-Vis), fluorescence spectrum (PL). ZnSe QDs assisted with ammonia were sphalerite, and with emission peak in the range of 380~405nm. The optimal condition was following: Zn/Se ratio was 5, Zn/MPA ration was 0.25, reaction temperature was 110 °C and reaction time was 6 h. Under the optimal condition, ZnSe QDs with intrinsic emission QY of 47% and diameter of 3.8±0.3 nm can be obtained. The ZnSe QDs prepared in this study were expected to replace toxic Cd-related QDs in biomarkers, violet and blue light solid luminescent devices, and provide excellent parent materials for the doped ZnSe QDs system.

Synthesis, performance and growth mechanism of silver nanoparticle coated SERS fiber probe

2019 ◽  
Vol 107 (3) ◽  
pp. 305
Author(s):  
Mengmei Geng ◽  
Yuting Long ◽  
Tongqing Liu ◽  
Zijuan Du ◽  
Hong Li ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Absorption Spectrum ◽  
Reaction Time ◽  
Growth Mechanism ◽  
Fiber Optic ◽  
Fiber Optic Probe ◽  
Visible Absorption ◽  
Fiber Probe ◽  
Surface Enhanced Raman ◽  
Optic Probe

Surface-enhanced Raman Scattering (SERS) fiber probe provides abundant interaction area between light and materials, permits detection within limited space and is especially useful for remote or in situ detection. A silver decorated SERS fiber optic probe was prepared by hydrothermal method. This method manages to accomplish the growth of silver nanoparticles and its adherence on fiber optic tip within one step, simplifying the synthetic procedure. The effects of reaction time on phase composition, surface plasmon resonance property and morphology were investigated by X-ray diffraction analysis (XRD), ultraviolet-visible absorption spectrum (UV-VIS absorption spectrum) and scanning electron microscope (SEM). The results showed that when reaction time is prolonged from 4–8 hours at 180 °C, crystals size and size distribution of silver nanoparticles increase. Furthermore, the morphology, crystal size and distribution density of silver nanoparticles evolve along with reaction time. A growth mechanism based on two factors, equilibrium between nucleation and growth, and the existence of PVP, is hypothesized. The SERS fiber probe can detect rhodamin 6G (R6G) at the concentration of 10−6 M. This SERS fiber probe exhibits promising potential in organic dye and pesticide residue detection.

Sign in / Sign up

Export Citation Format

Share Document