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1.
纳米碳酸锌的制备和热分解动力学参数的测定   总被引:3,自引:0,他引:3  
Nanosized zinc carbonate was prepared in the droplet of nano-reactor based on microemusion. The influences of the concentration of the surfactant and reactant on the diameter of nanoparticles were studied and the kinetic pa-rameters of thermal decomposition reaction were determined. It can be shown from experimental results, the di-ameter of the droplet in the microemulsion which have dissolved reactant zinc nitrate and sal volatile is between 4.9nm and 7.7nm, 6.2nm and 12.4nm, respectively. Nanosized zinc carbonate prepared by the method of mi-croemusion has shown good dispersion, narrow distribution and light agglomeration. The particle size of nanosized zinc carbonate is between 5nm and 40nm, and its kinetic parameters of thermal decomposition reaction-activation energy E and reaction order n are 110kJ·mol-1 and 0.9, respectively.  相似文献   

2.
Cuprous oxide (Cu2O) nanocubes have successfully been prepared through a simple and novel method by heating Cu(ethyl acetoacetate)2 (Cu(EAC)2) and poly(ethyleneglycol) (PEG) in the absence of other chemicals. The PEG acted as the reducing agent as well as the stabilizer. The XRD results indicated that no metal Cu or CuO developed in the preparation process, and only Cu2O nanoparticles with the cuprous structure were produced. The TEM images revealed that all the Cu2O nanoparticles were cubic-shaped or square-shaped particles. The size and shape of Cu2O nanocubes were dependent on concentrations of the Cu(Ⅱ) precursor, reactant temperatures, and chain length of PEGs. It is interesting that the reducing reactivity of PEG was sensitive to its chain length, and the reduction reaction activity was drastically dropped with the decreasing of polymer′s chain length.  相似文献   

3.
Nano-sized HfO2, C and C/HfO2 powders obtained through hydrothermal process have been investigated by XRD, TEM and FTIR, and Different precursors, namely Hafnium(Ⅱ) oleate and Hafnium(Ⅱ) hydroxide derived from homogeneous precipitation method, have been chosen for the synthesis of nanometric HfO2 via hydrothermal process. The results indicate that using the former material as the precursor under identically hydrothermal process can yield finer HfO2 nanoparticles, compared to using the latter. Nano-sized Carbon of about 100 nm with square morphology and narrow size distribution can be obtained through hydrothermal reaction of sucrose solution at 200 ℃ for 6 h. The addition of as-synthesised Carbon nanoparticles into the hydrothermal process of HfO2 powder can produce C/HfO2 composite powders with core-shell structure.  相似文献   

4.
Cu1-xAgxI(x=0.5~0.6)纳米微粒的制备与表征   总被引:1,自引:0,他引:1  
In the presence of PVPK30,Cu1-xAgxI nanoparticles were prepared by ion exchange reaction.The product was characterized by FT-IR,XRD,TEM,EDS and SPS,respectively.It was found that the value of x is ap-proximately 0.5~0.6and the average diameter of the nanoparticles is 10~20nm.The product shows surface photovoltage property of semiconductor and the existence of Cu+ greatly enhances the separation efficiency of photoinduced electron-hole pairs.Meanwhile,SPS of Cu1-xAgxI nanoparticles with different X (Ag/I)value had been investigated. The results show that when X is 0.5~0.576, the SPS intensity of Cu1-xAgxI nanoparticles is highest.  相似文献   

5.
羟基功能化离子液体中Ag纳米材料的制备及结构表征   总被引:2,自引:0,他引:2  
Ag nanoparticles were prepared using hydroxyl-functionalized ionic liquids as reductant and reaction medium. Nanoparticles with different particle sizes were obtained by using ionic liquids with different structures, while nanorods were harvested when the reaction temperature was increased. The materials obtained were investigated by XRD and TEM. The results indicate that the crystal is in face-centred cubic structure for both of Ag nanoparticles and nanorods, and the diameter of Ag nanoparticles prepared in 1-ethoxyl-3-methyl imidazolium tetrafluoroborate ([C2OHmim]BF4), 1-(4′-hydroxyl)butyl-3-methyl imidazolium tetrafluoroborate ([C4OHmim]BF4) and 1-(6′-hydroxyl)hexyl-3-methyl imidazolium tetrafluoroborate ([C6OHmim]BF4) ionic liquid is about 25, 15 and 10 nm, respectively. And the diameter of Ag nanorods is about 200 nm and 2 μm in length. Finally, the formation mechanism of Ag nanoparticles and nanorods is proposed.  相似文献   

6.
Er-doped YF3 nanoparticles were prepared from quaternary microemulsions of cetyltrimethyl ammonium bromide, n-butanol, n-octane and water with oil to water(mass percent of ω(CTAB)=19.04%, ω(n-butanol)=15.24%, ω(n-octane)=51.40%. The nanofluorides were characterized by X-ray power diffraction and infrared fluorescence spectroscopy. The results of XRD are in agreement with the PDF#74-911 of YF3. The average grain size is about 30 nanometer as estimated by Scherrer Formula. ESEM images show that the diameter of BaF2∶Er3+ nanoparticles is 35 nm. The emission of infrared fluorescence spectroscopy of the predominant peak is located at 1 547 nm and the up-conversion optical properties measured with 980 nm laser diode show red and green emissions.  相似文献   

7.
A novel coordination polymer [NaGa(dipic)2(H2O)2]n was synthesized by the reaction of gallium(Ⅲ) trichloride with Na-salt of 2,6-pyridinedicarboxylic acid and its crystal structure was determined by X-ray diffraction method. The crystal belongs to monoclinic, space group Cc; the unit cell parameters are a=1.502 9(3), b=1.228 1(3) and c=0.872 38(17) nm, β=92.85(3)°, and Z=4, V=1.608 2(6) nm3, F(000)=920. Infrared, electronic absorption, 1H NMR spectra, as well as the thermal behavior are reported. The antibacterial activity of the gallium(Ⅲ) complex has been studied against Escherichia coli, Bacillus subtilis and Staphylococcus aureus in order to check its potential for chemotherapy agent. The activity is notable and higher than that of the H2L. CCDC: 240619.  相似文献   

8.
Na掺杂对锆酸锂吸收CO2性能的影响   总被引:1,自引:0,他引:1       下载免费PDF全文
By using Li2CO3, ZrO2, and Na2CO3 as starting materials, sodium-doped Li2(1-x)Na2xZrO3 absorbents were prepared by high-temperature solid-state reaction. The crystal structure of the lithium zirconate material was analyzed using a X-ray powder diffractometer (XRD), the microstructure of all the samples was observed using the method of scanning electron microscopy (SEM) and the CO2-absorption ability of the lithium zirconate material was studied using a thermogravimetric analyzer (TG). It was found that Li2(1-x)Na2xZrO3 absorbent with x=0.02 possesses the best performance. As much as (25 ± 0.4)% (wt) of CO2 was absorbed by such an absorbent in an atmosphere consisting of 20% (wt) CO2 and 80% (wt) air at 500 ℃ within 3 h. After 10 cycles of absorption-desorption this absorbent lost only 0.9% of its CO2-absorption capacity. No remarkable change in particle size and pH was observed.  相似文献   

9.
低维纳米材料CuI的制备   总被引:3,自引:0,他引:3       下载免费PDF全文
Low-dimensional CuI nanomaterials were synthesized in microemulsions containing cyclohexane, Triton X-100, n-pentanol and aqueous solution. The redox reaction took place in this system and the final products CuI were obtained. It′s found that the morphology of CuI could be influenced a great deal by the experimental param-eters such as w0 (the molar ratio of water to surfactant), reactant concentration and the aging time. Hexagonal or shuttle-like CuI flakes, nanoparticles and nanofibers could be prepared respectively under certain conditions.  相似文献   

10.
掺钇锆酸锶-TiO2复合光催化剂的制备及性能研究   总被引:2,自引:0,他引:2  
SrZrO3 particles were prepared by a co-precipitation method and Sr(Zr1-xYx)O3-δ -TiO2 composite particles were then synthesized by Sr(Zr1-xYx)O3-δ and titanium dioxide. The composite particles were characterized by XRD, SEM, FTIR and TG-DTA techniques. The photocatalytic degradation of methylene blue (MB) in aqueous solution was used as a probe reaction to evaluate the photocatalytic activity of the composite particles. The effect of the preparation method for SrZrO3, doping content of yttrium and TiO2 amount in the composite particles on the photocatalytic activity of composite particles was also discussed. The results show that the methylene blue solution could be completely degraded by Sr(Zr1-xYx)O3-δ -TiO2 composite particles under UV-light or visible light irradiation. The photocatalytic activity of composite particles was higher than that of pure TiO2. The fast recombination of photogenerated electrons and holes were restrained by the heterojunction formed in composite particles. The particle of SrZrO3 prepared by co-precipitation was small, and the photocatalytic activity of composite particles prepared from this kind of SrZrO3 was higher than that of particles prepared by solid sintering method. The best doping content of yttrium is 5%. The optimal content of TiO2 in composite particles is 90wt%, 70wt%, respectively under UV-light and visible light irradiation, the degradation rates of MB are 98.8% and 93.5% , respectively after 50 min irradiation.  相似文献   

11.
In the system U–La–N a new phase of composition La2U2N5 was observed. The differaction pattern of this phase can be indexed with a tetragonal unit cell:a=8.43 Å,c=8.50 Å andc/a=1.008. The pseudocubic sub-cell withaca/2 is closely related to the CsCl-type.
Auszug aus der von der Technisch-Naturwissenschaftlichen Fakuktät der TU Wien approbierten Diplomarbait des Herrn Dipl.-Ing.J. Waldhart.  相似文献   

12.
The title complexes are used as intramolecular cyclization agents to yield under mild conditions and average to good yields 2-azetidinones from variously substituted 3-aminopropanoic acids. The reaction is found to proceed in all examined cases stereospecifically, with one exception. No marked difference with respect to yields and stereospecificity is noted among the four condensation systems.
2-Azetidinone aus 3-Aminopropansäuren und Ph3 P/CCl 4(CBr 4) oder Ph3 P/Br 2(I 2) als Kondensationsmittel
Zusammenfassung Die im Titel angegebenen Systeme wurden als Cyclisationsreagentien eingesetzt, um aus substituierten 3-Aminopropansäuren 2-Azetidinone unter milden Bedingungen und mit durchschnittlichen bis guten Ausbeuten darzustellen. Mit einer Ausnahme läuft die Reaktion stereospezifisch. Bei den vier untersuchten Systemen wurde kein beträchtlicher Unterschied in bezug auf Ausbeute und Stereospezifität festgestellt.
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13.
The structure of Ca2As2O7 (a 0=7.05,b 0=9.30,c 0=4.89 Å; =101.3°; space groupC2/m-C 2h 3 ;Z=2) has been solved from 465 independent X-ray intensities collected on aWeissenberg-type diffractometer up to anR-factor of 2.4% for all intensities. The structure of Ca2As2O7 represents a further Thortveitite structure type.
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14.
LixNi0.8-yCo0.2ZnyOp的合成及电化学性能研究   总被引:1,自引:0,他引:1       下载免费PDF全文
A series of single-phase LixNi0.8-yCo0.2ZnyOp(0.96 ≤x≤ 1.10, 0 ≤y≤ 0.05, 2 ≤p≤ 2(1+y) ) (different in the y values) were synthesized by a two-step solid state reaction method, in which LiOH·H2O, Zn-doped spherical Ni(OH)2 and Co2O3 were used as the precursors. The ICP-AES analyses proved that the Zn-doped compounds synthesized had the nonstoichiometric form. The results of the XRD, SEM identified that the uniform particles of the as-prepared materials having a good layered structure were fine, narrowly distributed and well crystallized. The electrochemical performance test was carried out and the results showed that the as-prepared Zn-doped materials had not only a high capacity, but also a better cycling stability characterization than the un-doped one. The Li1.06Ni0.75Co0.22Zn0.03O2.03 material has an initial reversible capacity as high as 160.5mAh·g-1; and a first discharge efficiency 89.2%, and exhibits satisfactory cyclic stability with 90% retainable capacity after 50 cycles.  相似文献   

15.
A number of samples of sodium and silver phosphate glasses doped with various compositions of some transition metals viz. iron, manganese and zinc chlorides alongwith undoped samples of sodium and silver phosphate glasses were synthesized and characterized by X-ray diffraction, IR spectral, electrical conductivity and differential scanning calorimetry (DSC). The glass transition temperature (T g) and crystallization temperature (T c) values obtained from DSC curves were found to increase with increasing concentration of the dopant Fe/Mn/Zn chlorides in both sodium and silver phosphate glasses and the following sequence is observed: T g(–FeCl3)>T g(–MnCl2)>T g(–ZnCl2) T c(–FeCl3)>T c(–MnCl2)>T c(–ZnCl2) The increase in T g and T c values indicate enhanced chemical durability of the doped glasses. The electrical conductivity values and the results of FTIR spectral studies have been correlated with the structural changes in the glass matrix by the addition of different transition metal cations as dopants.  相似文献   

16.
The structural instability of the [NH4−n (CH3) n ]2HgCl4 group has been investigated. Consideration of different crystals of this family shows that the H-bonds, obviously, hinder the appearance of incommensurate modulation. The dependence of phase transition sequence on the sizes of cation and anion may be obtained only for crystals with simple cation. The appearance of H-bonds complicates the situation and, leads to gradual disappearance of IC phase in the A2BX4 family.  相似文献   

17.
Single-domain manganese ferrite nanoparticles have been synthesized with narrow particle size distribution using the combustion technique. Influence of fuel ratios on the as-prepared powders were characterized by XRD, SEM, VSM, N2 adsorption at −196 °C and conversion of cyclohexene at 200–400 °C. Ratios of fuel to cations were maintained variously at 0.0, 0.67, 1.33 and 2.67.The fuel to cations ratio of 2.67 gives better yield in the formation of nanocrystalline Mn ferrite and single-domain particles with a narrow range of size distribution. Maximum magnetization and coercivity values of the investigated ferrite are also greater for the ratio of 2.67. These values measured at room temperature are found to be 68.58 emu/g and 62.57 Oe, respectively. The BET surface area of the investigated solids was found to decrease by increasing the ratio between fuel and cations due to increasing the flame temperature. However, this treatment resulted in a significant increase in catalytic activity of the as-synthesized solids. All solids investigated behaved as dehydrogenation catalysts. The change in fuel/cations ratios did not alter the mechanism of dehydrogenation of cyclohexene, but increased the concentration of active sites involved in the catalyzed reaction.  相似文献   

18.
Na3Fe2S4 has been prepared from Na2S, S and Fe. It crystallizes in space group Pnma,a=6.6333 (5) Å,b=10.675 (1) Å,c=10.677 (2) Å,Z=4. The crystal structure, as determined from single crystal four-circle diffractometer data (R=2.8%), consists of sk/1[FeS2]-chains formed by slightly distorted edge sharing [FeS4]-tetrahedra, the iron atoms having a formal valency of +2.5. The sodium ions are approximately octahedrally coordinated. Exposed to air, Na3Fe2S4 readily takes up water to form a hydrate by a pertially topochemical reaction.
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19.
研究了以多孔二氧化硅微球和活性炭为载体制备NOx吸附/还原催化剂的方法,摸索了最佳Ce/Co物质的量的比例。采用低温氮吸附方法测定了样品的BET比表面和孔容,利用XRD方法表征了样品中所掺杂的金属元素的晶型。研究发现:当nCe/nCo=75/25时,材料获得最佳NOx吸附能力,当以多孔二氧化硅微球作载体时,材料对于NOx的吸附主要来自CoOx和CeO2的二元氧化物;当以活性炭作为载体时,活性炭参与了NOx的吸附,因此其吸附容量大大提高。对NOx的吸附机理进行了探讨,并研究了样品的NH3还原性质。  相似文献   

20.
用放电 LIF实验装置,对CCl4/Ar混合气体放电产生CCl2自由基,再用541.52 nm激光将电子基态CCl2激励到激发态A 1B1(0,4,0)振动能级上,通过检测激发态CCl2时间分辨荧光信号,测得室温下CCl2(A 1B1)被烷烃类分子猝灭的实验结果,用我们提出的三能级模型分析处理实验数据,获得CCl2(A 1B1)态和CCl2(a 3B1)态的碰撞猝灭速率常数kA和ka值.  相似文献   

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