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1.
Synthesis and Structure of Polypyrrole Derivatives/V2O5 Nanocomposites   总被引:1,自引:0,他引:1  
Poly ( N, N, N-trimethyl ( 2-pyrrol-l-yl ) ethyl ammonium iodide )/V2O5 ( PTPAI/V2O5) nanocomposites were synthesized by sol-gel method. This method involved formation of vanadium pentoxide xerogel in the prcscnce of polypyrrole derivatives solution. X-ray diffraction(XRD) indicated that the polypyrrole derivative particles encapsulated in the fibrous V2O5 network and the layered distance significantly increased from 1. 077 39 to 1. 354 56 nm. The interaction between polypyrrole and V2O5 in the ‘nanocomposites‘ was characterized by IR spectroscopy. The Scanning Electron Microscope(SEM) micrographs reveal the structural contrasts between the hybrid materials and the pristine vanadium oxide xerogel.  相似文献   

2.
This work is devoted to the synthesis and characterization of yttrium-doped SrBi2Nb2O9 ceramics prepared by three methods: solid state reaction, co-precipitation, and hydrothermal. Multiple characterizations, specifically scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR), were used to validate the structural feature. The crystallite size was estimated by Scherrer’s formula and the Williamson–Hall plot. The effect of the process on the band intensities of the FTIR spectra was investigated. The crystallite size and microstructure of ceramics prepared from different synthesis processes were strongly influenced by the sinterability. SEM images revealed nanograin ceramics for materials prepared by co-precipitation and hydrothermal methods and micrograin ceramics prepared by the solid state method. The synthesized compounds underwent phase transitions at 480–465°C. The dielectric and electrical properties of these Y-doped SrBi2Nb2O9 ceramics appear to be dependent on the grain size.  相似文献   

3.
Fabrication and S-F-codoping of TiO2 nanotubes were carried out by a one-step electrochemical anodization process to extend the photoresponse of TiO2 to the visible-light region. The prepared samples were annealed in air and detected by SEM, XRD, XPS and UV-vis DRS spectrophotometer. The results showed that the average tube diameter of the nanotubes was 150 nm and the average tube length was 400 nm. The doped TiO2 nanotubes exhibited strong absorption in visible-light region. Photoelectrocatalytic degradation efficiency of 4-CP over S-F-codoped TiO2 nanotubes was 39.7% higher than that of only-F-doped sample. Moreover, sulfur and fluorine codoped into substitutional sites of TiO2 had been proven to be indispensable for strong response and high photocatalytic activity under visible light, as assessed by XPS.  相似文献   

4.
The compression behavior of Ni77P23 amorphous alloy is investigated at room temperature in a diamond-anvil cell instrument using insitu high pressure energy dispersive X-ray diffraction with a syn- chrotron radiation source. The equation of state is determined by fitting the experimental data accord- ing to Birch-Murnaghan equation: -ΔV/V0=0.08606P-3.2×10-4P2 5.7×10-6P3. It is found that the structure of Ni77P23 amorphous alloy is stable under pressures up to 30.5 GPa.  相似文献   

5.
A spherical-like Ni0.6Co0.2Mn0.2(OH)2 precursor was tuned homogeneously to synthesize LiNi0.6Co0.2Mn0.2O2 as a cathode material for lithium-ion batteries. The effects of calcination temperature on the crystal structure, morphology, and the electrochemical performance of the as-prepared LiNi0.6Co0.2Mn0.2O2 were investigated in detail. The as-prepared material was characterized by X-ray diffraction, scanning electron microscopy, laser particle size analysis, charge-discharge tests, and cyclic voltammetry measurements. The results show that the spherical-like LiNi0.6Co0.2Mn0.2O2 material obtained by calcination at 900℃ displayed the most significant layered structure among samples calcined at various temperatures, with a particle size of approximately 10 μm. It delivered an initial discharge capacity of 189.2 mAh·g-1 at 0.2C with a capacity retention of 94.0% after 100 cycles between 2.7 and 4.3 V. The as-prepared cathode material also exhibited good rate performance, with a discharge capacity of 119.6 mAh·g-1 at 5C. Furthermore, within the cut-off voltage ranges from 2.7 to 4.3, 4.4, and 4.5 V, the initial discharge capacities of the calcined samples were 170.7, 180.9, and 192.8 mAh·g-1, respectively, at a rate of 1C. The corresponding retentions were 86.8%, 80.3%, and 74.4% after 200 cycles, respectively.  相似文献   

6.
Spinel compounds LiNi0.5Mn1.3Ti0.2O4 (LNMTO) and Li4Ti5O12 (LTO) were synthesized by different methods. The particle sizes of LNMTO and LTO are 0.5–2 and 0.5–0.8 μm, respectively. The LNMTO/LTO cell exhibits better electrochemical properties at both a low current rate of 0.2C and a high current rate of 1C. When the specific capacity was determined based on the mass of the LNMTO cathode, the LNMTO/LTO cell delivered 137 mA·h·g−1 at 0.2C and 118.2 mA·h·g−1 at 1C, and the corresponding capacity retentions after 30 cycles are 88.5% and 92.4%, respectively.  相似文献   

7.
The synthesis process of LiCo0.3Ni0.7O2 was investigated by FT-IR, mass spectroscopy, elemental analysis, SEM, BET, TG/DTA and XRD in this paper. The results revealed that lithium and transition metal ions were trapped homogeneously on an atomic scale throughout the precursor. Li2CO3, NiO and CoO are the intermediate products obtained after decomposition of the precursor and Li2CO3 undergoes direct reactions with NiO and CoO to form LiCo0.3Ni0.7O2. Moreover, the kinetics of formation of LiCo0.3Ni0.7O2 by dtrate sol-gel method is faster than the case of the conventional solid-state reaction between lithium carbonate and corresponding reactants. The single phase of LiCo0.3Ni0.7O2 was synthesized at temperature as low as 550℃. The discharge capacity of LiCo0.3Ni0.7O2 increases from 127 to 185 mAh/g as the caldnation temperature increasing from 550 to 750℃. After 100 cycles, the discharge capacity of the sample calcined at 750℃ is 155 mAh/g. The electrochemical study shows that the LiCo0.3Ni0.7O2 has high discharge capacity and good cycling behavior for lithium ion batteries.  相似文献   

8.
By combination of DC reactive magnetron sputtering with multiple arcplating, the alternating C3N4/TiN compound film is deposited onto HSS. The core level binding energy and the contents of carbon and nitrogen are characterized by X-ray photoelectron spectrum. X-ray diffraction (XRD) shows that compound thin film contains hard crystalline phases of α-C3N4 and β-C3N4. The Knoop microhardness in the load range of 50, 5–54, 1 GPa is measured. According to acoustic emission scratch test, the critical load values for the coatings on HSS substrates are in the range of 40–80 N. The metal coated with C3N4/TiN compound films has a great improvement in the resistance against corrosion. Many tests show that such a coating has a very high wearability. Compared with the uncoated and TiN coated tools, the C3N4/TiN coated tools have a much longer cutting life. Foundation item: Supported by the National Natural Science Foundation of China (19875037) Biography: Wu Da-we( (1941-), male, Professor, research direction; thin film and its application.  相似文献   

9.
The effects of temperature on corrosion and the electrochemical behavior of Ni82.3Cr7Fe3Si4.5B3.2 glassy alloy in HCl, H2SO4, and H3PO4 acids were studied using AC and DC techniques. Impedance data reveal that the susceptibility to localized corrosion increases with increasing temperature. Potentiodynamic polarization curves reveal that the bulk glassy alloy is spontaneously passivated at all the investigated temperature in H2SO4 and H3PO4 solutions. A localized corrosion effect in HCl solution is clearly observed. The apparent activation energies in the regions of Tafel, active, and passive, as well as the enthalpies and entropies of the dissolution process were determined and discussed. The high apparent activation energy (Ea) value for H3PO4 solution in Tafel region is explained by the low aggressivity of PO43- ions.  相似文献   

10.
A gas diffusion electrode (air electrode) with a high current efficiency of electro-synthesizing H2O2 using O2 in air was prepared. The several systems with air electrode as cathode of electro-synthesizing H2O2 on the reaction spot for degrading aniline in aqueous—electro-Fenton system, photo-excitation electro-H2O2 system and photo-electro-Fenton system, were developed. The rates of decomposition of H2O2 and mineralization of aniline were experimentally measured respectively under different conditions, and the results indicated there has an excellent parallel relation between decomposition rate of H2O2 and mineralization rate of aniline. Especially, photo-electro-Fenton system, where H2O2 is decomposed the fastest, is the best system of oxidizing and degrading organic toxicants. Compared photo-electro-Fenton system with photo-Fenton system, important role is revealed in the interface of air electrode. In this paper, the mineralization mechanism of aniline in the photo-electro-Fenton system was also discussed. Foundation item: Supported by the National Natural Science Foundation of China (200710026) and Foundation of Environmental Sciences Academy of Jiangsu Province. Biography: Cao xiao-yu (1979-), male, Master candidate, research direction: Electrochemistry  相似文献   

11.
The Sr3SiO5:Eu^2+ phosphor was synthesized by high temperature solid-state reaction. The emission spectrum of Sr3SiO5:Eu^2+ shows two bands centered at 487 and 575 nm, which well agree with the theoretic values of emission spectrum. The excitation spectrum for 575 nm emission center has several excitation bands at 365, 418, 458 and 473 nm. And the results show that the emission spectrum of Sr3SiO5:Eu^2+ is influenced by the Eu^2+ concentration. The relative emission spectra of the white-emitting InGaN-based YAG:Ce^3+ LED and Sr3SiO5:Eu^2+ LED were investigated. The results show that the color development of InGaN-based Sr3SiO5:Eu^2+ is better than that of InGaN-based YAG:Ce^3+, and the CIE chromaticity of InGaN-based Sr3SiO5:Eu^2+ is (x=0.348, y=0.326).  相似文献   

12.
Nanoparticles of Ce0.6Zr0.35Y0.05O2 (CZY) solid solution have been prepared by the CTAB (hexadecyl-trimethyl ammonium bromide), CTAB-EG (ethylene glycol) templating, and CTAB-EG-NaCl (in which the pores of the precursor synthesized by the CTAB-EG method is filled by a certain amount of NaCl) method, respectively. The physical properties of these materials were characterized by means of tech-niques such as X-ray diffraction (XRD), high resolution scanning electron microscopy (HRSEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and N2 adsorp-tion-desorption measurements. The CZY samples synthesized by the above three methods display wormhole-like mesoporous morphology and cubic crystal structures. The materials are narrow in pore size distribution (averaged pore diameter = 5.3―7.1 nm), high in surface areas (95―119 m2/g), and large in pore volumes (0.16―0.18 cm3/g). It has been demonstrated that the introduction of NaCl is capable of retaining the pore structures of solid nanomaterials at high-temperature calcination.  相似文献   

13.
The electro-deoxidation of V2O3 precursors was studied. Experiments were carried out with a two-terminal electrochemical cell, which was comprised of a molten electrolyte of CaCl2 and NaCl with additions of CaO, a cathode of compact V2O3, and a graphite anode under the potential of 3.0 V at 1173 K. The phase constitution and composition as well as the morphology of the samples were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). 3 g of V2O3 could be converted to vanadium metal powder within the processing time of 8 h. The kinetic pathway was investigated by analyzing the product phase in samples prepared at different reduction stages. CaO added in the reduction path of V2O3 formed the intermediate product CaV2O4.  相似文献   

14.
The ruthenium-substituted polyoxometallic acid H6 [Ru(H2O)FeW 11O39 ]·18H2O was synthesized by stepwise acidification and stepwise addition of solutions of the component elements, and an ion-exchange-cooling method. The product was characterized using inductively coupled plasma spectrometry (ICP), Infrared Spectroscopy (IR), Ultraviolet Spectroscopy (UV), and X-ray diffraction (XRD). The results show that this complex has the Keggin structure. The determination of the thermal stability and proton conductivi...  相似文献   

15.
The crystal structure stability as well as electric conductance of (Sr/Ca)2CuO2Cl2 compound with K2NiF4 structure was investigated up to 31 GPa using diamond anvil technique. It seems that (Sr/Ca)2CuO2Cl2 is quite stable under pressure but with obvious anisotropic compressibility. The equation of state (EOS) obtained shows relative large bulk modulus.  相似文献   

16.
A coordination complex was synthesized from NiCl2 and dipeptide glycylglycine(GG). It was characterized by element analysis, NMR and TG methods, and then was determined to be Ni(C4HsN2O3)2Cl2. Using an isoperibolic reaction calorimeter, the standard molar enthalpy of formation of Ni(GG)2Cl2(solid) has been determined to be -(1 674.66±2.02) kJ · mol^-1 at 298.15 K.  相似文献   

17.
Ni(II)-dien complex was prepared and characterized by X-ray diffraction. The crystal belongs to triclinic system, space group P-1, with crystallographic parametersa=0.888 13(18) nm,b=0.890 10(18) nm,c=1. 591 8(3) nm, α=77.71(3)°, β=89.12(3)°, γ=61.24(3)°,Z=2. The two dien molecules coordinate to the central Ni atom, the six nitrogen atoms form a distorted octahedron. Preliminary pharmacological tests showed this complex had antitumor activity against HepG2 and HL-60 cell linesin vitro. Foundation item, Supported by the National Natural Science Foundation of China (29972034) Biography: Li Tao (1976-), male, Ph. D candidate, research direction: ophthalmology and chemicalbiology.  相似文献   

18.
Oxalic-acid-based co-precipitation method was employed to prepare LiNi2/3Mn1/3O2 sample with a high-ordered structure. Li+, Ni2+ and Mn2+ acetates were used as starting materials. The influence of the amount of lithium source in the starting materials on Li+ content, disorder of Li+-Ni2+ ions, and electrochemical performance has been investigated. Rietveld refinement shows that the sample prepared with 20% excess Li-source in the starting materials exhibits a perfect ordered structure. A specific discharge capacity is as high as 172 mAh/g at C/20 in the voltage range of 4.35–2.7 V. However, the cyclability is not satisfactory: about 25.3% fade in capacity was observed over 50 cycles. Chemically stable SiO2 was coated on the surface of LiNi2/3Mn1/3O2 particles. A significant improvement in cyclability was attained with 3 wt% SiO2 coating, which is ascribable to the protection of LiNi2/3Mn1/3O2 particles from being dissolved into the electrolyte.  相似文献   

19.
An orthogonal test was used to optimize the reaction conditions of roasting zinc oxide ore using (NH4)2SO4. The optimized reaction conditions are defined as an (NH4)2SO4/zinc molar ratio of 1.4:1, a roasting temperature of 440°C, and a thermostatic time of 60 min. The molar ratio of (NH4)2SO4/zinc is the most predominant factor and the roasting temperature is the second significant factor that governs the zinc extraction. Thermogravimetric–differential thermal analysis was used for (NH4)2SO4 and zinc mixed in a molar ratio of 1.4:1 at the heating rates of 5, 10, 15, and 20 K·min-1. Two strong endothermic peaks indicate that the complex chemical reactions occur at approximately 290°C and 400°C. XRD analysis was employed to examine the transformations of mineral phases during roasting process. Kinetic parameters, including reaction apparent activation energy, reaction order, and frequency factor, were calculated by the Doyle–Ozawa and Kissinger methods. Corresponding to the two endothermic peaks, the kinetic equations were obtained.  相似文献   

20.
This paper reports the thermoluminescence (TL) characteristics of lithium borate activated by Cu, Ag and P. The glow curves and spectra of thermoluminescence were measured, and the thermoluminescence response as a function of the absorbed dose and the fading behavior were studied. The results indicate that TL of this material has a low fading and wide linear dose response (10^-4-10^3 Gy).  相似文献   

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