共查询到20条相似文献,搜索用时 15 毫秒
1.
The ultrafine Mn2SnO4 nanoparticles with diameters of 5-10 nm have been prepared by thermal decomposition of precursor MnSn(OH)6. The MnSn(OH)6 nanoparticles precursor was synthesized by a hydrothermal microemulsion method. X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy and electron diffraction have been employed to characterize the crystal structures and morphologies of the as-prepared samples. High-resolution transmission electron microscopy observations revealed that the as-synthesized nanoparticles were single crystals. The thermal characterization was studied by differential thermal analysis and thermogravimetry analysis measurements. Electrochemical test showed that the Mn2SnO4 nanoparticles exhibited a high initial charge-discharge capacity of 1320 mAh/g. 相似文献
2.
Juan Wang Yunhua Xu Mirabbos Hojamberdiev Jianhong Peng Gangqiang Zhu 《Materials Science and Engineering: B》2009,156(1-3):42-47
Nano- and micro-scaled Eu-doped yttrium orthovanadate (YVO4:Eu3+) powders had been fabricated via disodium ethylenediamine tetraacetate (Na2EDTA)-assisted morphology controllable hydrothermal method in a wide pH range at 180 °C for 24 h. The as-synthesized samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and photoluminescence spectroscopy (PL). The results showed that the pH value of the synthesis solution played a key role in the formation of the final products with different morphologies, including ball-like micro-spheres, micro-spheres composed of submicron cubes and flower-like structures containing nano-plates. The photoluminescence measurement revealed that the luminescent properties of the samples were changed by varying their morphologies. The significant ball-like micro-spheres of YVO4:Eu3+ particles had been synthesized, and the luminescence intensity of them is the strongest one among all products. 相似文献
3.
Juan Wang Mirabbos Hojamberdiev Yunhua Xu Jianhong Peng 《Materials Chemistry and Physics》2011,125(1-2):82-86
YVO4:Eu3+ powders with different morphologies were fabricated by a simple hydrothermal method at 180 °C for 24 h in a wide pH range with the assistance of polyvinylpyrrolidone (PVP) as a nonionic surfactant. The as-synthesized samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and photoluminescence spectroscopy (PL). The obtained results showed that the pH value of synthesis solution played a key role in the formation of final products with different morphologies, such as, microspheres, irregular microspheres with grain-like nanoparticles, stone-like structures with regular short nanorods, and smooth rhombohedrons. The PL measurements revealed that the emission intensity of the samples was first decreased, and then increased with increasing the pH value due mainly to the increase in crystallinity and decrease in surface defects. 相似文献
4.
One-dimensional anatase TiO2 and hybrid TiO2/titanate nanostructures are synthesized by a simple low temperature solvothermal route followed by the Na+/H+ ion-exchange and final calcination process. We investigated the impact of reaction temperature, stirring conditions and cosolvent on the morphologies of the as-prepared nanostructures. Nanotubes and nanorods are formed in alkaline solution, while nanorods/nanowires and nanoporous nanoribbons are formed in alkaline water–ethanol and alkaline water–ethylene glycol mixed solvents, respectively. X-ray diffraction, Raman scattering and high-resolution transmission electron microscopy studies are employed to identify the structure and phase composition. The formation of different morphologies of the as-synthesized nanostructures is investigated by field emission scanning electron microscopy and transmission electron microscopy. The growth mechanism and reaction process of the as-prepared nanostructures are explained based on the experimental observations. The photoluminescence, optical absorption and the tuning of band gap of the prepared samples are also studied. This work will be valuable for understanding the growth mechanism of various nanostructured TiO2 and to explore the commercial applications of nanoporous nanoribbons of TiO2. 相似文献
5.
Z. Chen 《Materials Research Bulletin》2009,44(1):45-7261
CaWO4 and SrWO4 nanostructures have been synthesized via a simple microemulsion-mediated route. With careful control of the fundamental experimental parameters including the concentration of reactants, the reaction time and the temperature, the products with different morphologies of dumbbell, coral, rod and dendrite have been obtained, respectively. The possible formation mechanism of these unique morphologies has been proposed based on surfactant self-assembly under different experimental conditions. The as-synthesized CaWO4 samples with various morphologies exhibit different photoluminescence properties. X-ray powder diffraction, transmission electron microscopy, field-emission scanning electron microscopy, and luminescence spectroscopy were used to characterize these products. 相似文献
6.
Eu3+-doped TiO2 nanocrystals with three kinds of morphologies (nanorods, nanoparticles, and submicrospheres) have been successfully fabricated in cetyltrimethylammonium bromide (CTAB)/water/cyclohexane/n-pentanol reverse micelle by hydrothermal method for the first time and their photoluminescence (PL) properties have also been studied. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), FT-IR, and PL spectra were used to characterize the samples. The acidic and alkaline conditions of the microemulsion play an important role in determining the geometric morphologies of the final products. TiO2:Eu3+ with three different morphologies all exist only in anatase phase and show high luminescence intensity without further calcinations, which show its advantages of energy saving. The shape of emission spectra was independent of the morphologies of the products but the luminescence intensity of the TiO2:Eu3+ materials is strongly dependent on their morphology. The results show that TiO2:Eu3+ nanorods possess the strongest luminescence intensity among the three nanostructured samples. 相似文献
7.
Orthorhombic single-crystalline cerium carbonate hydroxide (CeCO3OH) with one-dimensional (1D) microstructures has been successfully synthesized by a facile sonochemical reaction between cerous nitrate and urea. These 1D microstructures were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM). The as-synthesized CeCO3OH has uniform lengths and good dispersion. Synthetic parameters, such as the concentration of reagents, were found to have close relationship with the morphologies and sizes of the final products. The ultrasound-induced oriented attachment growth mechanism has been proposed for the possible formation mechanism of sample. Room-temperature photoluminescence of CeCO3OH samples with different morphologies has also been investigated. 相似文献
8.
Gangqiang Zhu Peng Liu Mirabbos Hojamberdiev Bao Ge Yun Liu Hongyan Miao Guoqiang Tan 《Materials Chemistry and Physics》2009,118(2-3):467-472
Single-phase RMn2O5 (R = Gd and Sm) nano- and microstructures have been successfully synthesized via a simple hydrothermal process at 250 °C for 24 h using NaOH as mineralizer. X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and selective area electron diffraction patterns (SAED) were used to characterize the as-synthesized GdMn2O5 and SmMn2O5 samples. The effect of NaOH concentration and the molar ratio of Mn2+/Mn7+ on the morphology and size of the final products was studied, and a possible formation mechanism of RMn2O5 (R = Gd and Sm) nanoplates and nanorods under hydrothermal conditions was proposed. 相似文献
9.
Youcun Chen Zhongyu Duan Yulin Min Mingwang Shao Yinguo Zhao 《Journal of Materials Science: Materials in Electronics》2011,22(8):1162-1167
In this paper, different crystallographic types and crystal morphologies of MnO2 nanomaterials have been selectively synthesized by a simple hydrothermal route. α-MnO2 nanowires, and γ-MnO2 hollow hierarchical spheres have been prepared by a sodium dodecyl benzenesulfonate (SDBS)-assisted hydrothermal treatment
method. The as-synthesized samples were characterized by XRD, SEM, TEM, and HRTEM. Furthermore, the obtained different kinds
of MnO2 nanostructures were found to exhibit favorable photocatalytic activity in organic dyestuff such as methyl orange, showing
potential applications in photocatalysis. And the results showed that γ-MnO2 hollow micro-spheres exhibited superior photocatalytic activities to α-MnO2. 相似文献
10.
In this paper, the Tb3+-doped GdPO4·H2O nanorods and nanobundles have been synthesized by the hydrothermal method with and without glycine, respectively. The X-ray powder diffraction (XRD), thermogravimetric and differential thermal analysis (TG–DTA), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), energy-dispersive spectra (EDS) and photoluminescence (PL) were employed to characterize the as-obtained products. It was found that the addition of glycine and the pH value have crucial influences on the formation of the resulting morphologies and sizes. The possible formation mechanisms for GdPO4·H2O:Tb3+ nanorods and nanobundles were put forward. A detailed investigation on the photoluminescence of GdPO4·H2O:Tb3+ different samples revealed that the luminescent properties of products are strongly correlated with the morphologies, sizes, coordination environment and crystal field symmetry. 相似文献
11.
《Materials Letters》2007,61(8-9):1798-1800
Cu11(OH)14(CrO4)4 nanobelts have been synthesized by hydrothermal method in the absence of any surfactants. The as-synthesized products are characterized by X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. The average thickness, widths and lengths of the nanobelts are about 15 nm, 40 nm, and several micrometers, respectively. It is interesting that Cu11(OH)14(CrO4)4 nanobelts are very sensitive to electron beam illumination. The influences of the reaction temperature on the morphologies of the resulting products have been investigated. 相似文献
12.
AbstractZeolite faujasite (FAU), Linde type A (LTA) and FAU/LTA composite have been synthesized using tetramethylammonium cation (TMA+) as template, by adjusting only the concentration of Na+ ions in the initial solution (1.00 Al2O3 4.36 SiO2 : 2.39 (TMA)2 O : β Na2 O : 249.00H2 O). Na+ ions alter the phase composition of the product more than TMA+ or OH? ions. When Na2 O concentration [Na2 O] increases from 0.024 to 0.168, the product gradually changes from pure FAU to pure LTA via the formation of FAU/LTA composite with increasing LTA fraction. Interestingly, the induction periods of FAU and LTA in the FAU/LTA composite zeolite ([Na2 O] is 0.072) are both 13 h, quite different from the induction periods of their individual pure phases—45 h for FAU and 4 h for LTA. During the crystallization, the LTA/(FAU + LTA) fraction in the composite zeolite decreases in a nearly linear fashion. Scanning electron microscopy, thermogravimetry and differential thermal analysis indicate some difference between the properties of the FAU/LTA composite zeolite and of the mechanical mixture. 相似文献
13.
《Materials Letters》2007,61(11-12):2147-2150
Pure copper nanocrystallites and cuprous oxide nanorods have been synthesized via solvothermal treatment of CuSO4 or CuSO4·5H2O and NaOH in pure ethanol and mixed solution of ethanol and deionized water at 140 °C for 10 h, respectively. Transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) were used to investigate the different morphologies of the as-synthesized products. X-ray powder diffraction (XRD) and selected area electron diffraction (SAED) were applied to characterize the composition and crystal phases of the products. It was proposed that the reducibility of ethanol was influenced by temperature and the addition of deionized water in the formation of different phases, which were realized by carefully controlling the experimental conditions. 相似文献
14.
Controlled synthesis of different morphological YF3 crystalline particles at room temperature 总被引:1,自引:0,他引:1
YF3 crystalline particles with different crystal structures and different morphologies have been synthesized via a simple solution route by varying the fluoride source (NH4F, HF, NH4F·HF) and molar ratio of Y3+/F− at room temperature. They were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray photoelectron spectrum (XPS). 相似文献
15.
In order to prepare the pure (K, Na)NbO3(KNN) particles with higher crystallinity, the high temperature mixing method (HTMM) under hydrothermal conditions was carried out in this work. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and high-resolution transmission electron microscopy (HRTEM). The results indicate that the KNN particles size decrease gradually with the increase of mineralization concentration in the starting solution. The ratio of K+/(K+ + Na+) in the starting solution has a great effect on the phase of the products, and several phases coexist in the product when the ratio of K+/(K+ + Na+) in the starting solution is 0.7. 相似文献
16.
The porous sphere-like ZnO inorganic-organic nanocomposites have been prepared by self-assembly at the present of CTAB (cetyltrimethylammonium bromide, CH3(CH2)15N+(CH3)3Br−) surfactant on the titanium substrate. After high temperature oxidation, all the organic were removed and the porous sphere-like ZnO dendrite nanocrystals were obtained. The resultant products have been characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The XRD pattern shows that the as-synthesized porous sphere-like is multilayered inorganic-organic nanocomposite, and the sample calcined at 500 °C for 2 h has a hexagonal wurtzite crystal structure. FE-SEM and TEM images demonstrate that porous sphere-like ZnO dendrite nanocrystals are formed. A possible formation mechanism is preliminary proposed for the formation of the novel nanostructure. 相似文献
17.
《Advanced Powder Technology》2014,25(1):372-378
ZnO microstructures of different morphologies were synthesized by the sol–gel assisted hydrothermal method using Zn(NO3)2, citric acid and NaOH as raw materials. Twining-hexagonal prism, twining-hexagonal disk, sphere and flower-like ZnO microstructures could be synthesized only through controlling the pH of the hydrothermal reaction mixture at 11, 12, 13 and 14, respectively. The as-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM). Optical properties were examined by UV–Vis absorption/diffuse reflectance spectroscopy and room-temperature photoluminescence measurements (PL). Photocatalytic activities of the samples were evaluated by degradation of Reactive Blue 14 (KGL). The results indicated that the flower-like ZnO composed of nanosheets possessed superior photocatalytic activity to other ZnO microstructures and commercial ZnO, which could be attributed to the morphology, surface defects, band gap and surface area. The formation mechanisms of different ZnO morphologies were also investigated based on the experimental results. 相似文献
18.
In this study, YPO4:Eu3+ microspheres with different Eu3+ dosage concentration were fabricated by a facile hydrothermal route at 200 °C for 10 h in the presence of citric acid. The YPO4:Eu3+ samples were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and luminescence spectroscopy. The XRD results reveal that the YPO4:Eu3+ samples presented a tetragonal structure. The TEM and SEM observations demonstrate that the YPO4:Eu3+ samples with uniform sphere-like morphologies can be obtained at 200 °C for 10 h. The sizes of samples are in the range of 2–2.2 μm. The room temperature luminescence properties of YPO4:Eu3+ samples were studied using an excitation wavelength of 227 nm. The emission spectrum displays the bands associated to the 5D0 → 7FJ (J = 1, 2 and 4) electronic transitions characteristics of the Eu3+ cations at different positions. The influence of Eu3+ dosage concentration on luminescence properties of YPO4:Eu3+ microspheres were studied carefully. 相似文献
19.
Ming Zhang De-Jun Chen Rui-Zhi Wang Jiu-Ju Feng Zhengyu Bai Ai-Jun Wang 《Materials science & engineering. C, Materials for biological applications》2013,33(7):3980-3985
Single crystalline flower-like Bi2S3 nanostructures were successfully synthesized via a simple, facile and green hydrothermal method, with the assistance of D-penicillamine. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), and found their morphologies mainly depend on the ratios of Bi3 + to D-penicillamine, as well as the reaction temperature and time. And the possible growth mechanism has been discussed in some detail. In addition, the as-prepared Bi2S3 nanoflowers show good hydrogen storage ability. This strategy can be potentially expanded to prepare other metal chalcogenides materials. 相似文献
20.
Renyan Pei Zhijian Tian Ying Wei Keda Li Yunpeng Xu Huaijun Ma 《Materials Letters》2010,64(19):2118-2121
Several aluminophosphate molecular sieves were synthesized ionothermally, in ionic liquid 1-butyl-3-methyl imidazolium bromide ([BMIm]Br) with adding various quaternary ammonium cation (quats, including tetramethyl ammonium (TMA+), choline, tetraethyl ammonium (TEA+), tetrapropyl ammonium (TPA+) and tetrabutyl ammonium (TBA+)). These products were characterized by X-ray diffraction (XRD), 13C nuclear magnetic resonance (NMR) and scanning electron microscope (SEM). The result indicates that the crystallization pathway is changed by adding these quats. AlPO4-42 (IZA code LTA) crystallizes when TMA+ is added in the system, AlPO4-5 (AFI) crystallizes when choline or TEA+ is added, and the AlPO4-11 (AEL) crystallizes when TPA+ or TBA+ is added. 13C NMR analysis indicates that these introduced quats may either replace the [BMIm]+ to act as template alone, or direct structures cooperatively with the [BMIm]+, or in some cases they cannot change the original structure directing effect of [BMIm]+. 相似文献