首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Monodispersed colloidal copper oxide nanoparticles were synthesized by water-in-oil microemulsion using CuCl 2·H2O and NaOH.The effect on CuO particle size was studied by varying the water-to-surfactant molar ratio,precursor concentration and molar ratio of NaOH to CuCl2.The morphology,size and size distribution of the particles were studied by transmission electron microscopy and dynamic light scattering.Dispersion destabilization of the colloidal copper oxide nanoparticles was detected by a Turbiscan apparatus.CuO/γ-Al2O3 catalysts were prepared by dispersing highly stable CuO nanoparticles on γ-alumina by mechanical stirring.The catalysts were analyzed by scanning electron microscopy,transmission electron microscopy,X-ray photoelectron,and X-ray diffraction,which confirmed the uniform dispersion of CuO on the support.The reduction of the nitro aromatic compounds,4-nitrophenol,3-nitrophenol,and 2-nitrophenol,were studied.The CuO/γ-Al2O3 catalysts were active for the reduction of these nitro aromatic compounds.  相似文献   

2.
Monodispersed colloidal copper oxide nanoparticles were synthesized by water-in-oil microemulsion using CuCl 2·H2O and NaOH.The effect on CuO particle size was studied by varying the water-to-surfactant molar ratio,precursor concentration and molar ratio of NaOH to CuCl2.The morphology,size and size distribution of the particles were studied by transmission electron microscopy and dynamic light scattering.Dispersion destabilization of the colloidal copper oxide nanoparticles was detected by a Turbiscan apparatus.CuO/γ-Al2O3 catalysts were prepared by dispersing highly stable CuO nanoparticles on γ-alumina by mechanical stirring.The catalysts were analyzed by scanning electron microscopy,transmission electron microscopy,X-ray photoelectron,and X-ray diffraction,which confirmed the uniform dispersion of CuO on the support.The reduction of the nitro aromatic compounds,4-nitrophenol,3-nitrophenol,and 2-nitrophenol,were studied.The CuO/γ-Al2O3 catalysts were active for the reduction of these nitro aromatic compounds.  相似文献   

3.
Ultrathin MoS2nanosheets were prepared in high yield using a facile and effective hydrothermal intercalation and exfoliation route. The products were characterized in detail using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results show that the high yield of MoS2nanosheets with good quality was successfully achieved and the dimensions of the immense nanosheets reached 1 μm–2 μm. As anode material for Li-ion batteries, the as-prepared MoS2nanosheets electrodes exhibited a good initial capacity of 1190 mAh g-1and excellent cyclic stability at constant current density of 50 mA g-1. After 50 cycles, it still delivered reversibly sustained high capacities of 750 mAh g-1.  相似文献   

4.
Ultrathin MoS2nanosheets were prepared in high yield using a facile and effective hydrothermal intercalation and exfoliation route. The products were characterized in detail using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results show that the high yield of MoS2nanosheets with good quality was successfully achieved and the dimensions of the immense nanosheets reached 1 μm–2 μm. As anode material for Li-ion batteries, the as-prepared MoS2nanosheets electrodes exhibited a good initial capacity of 1190 mAh g-1and excellent cyclic stability at constant current density of 50 mA g-1. After 50 cycles, it still delivered reversibly sustained high capacities of 750 mAh g-1.  相似文献   

5.
β-Co(OH)2 and Mg(OH)2 nanoplates were synthesized via a facile template-free hydrothermal approach.The different conditions of preparation and catalytic properties of the products were studied and discussed.The products were characterized by X-ray diffraction,transmission electron microscopy,scanning electron microscopy,selected area electron diffraction(SAED),and gas chromatograph.  相似文献   

6.
CoFe2O4/TiO2 magnetic composite films were prepared using the sol-gel method with tetrabutyltitanate and metallic chlorates as starting materials. The effects of heat treatment temperatures on micro- structures and on magnetic properties were studied. The microstructure and properties of the samples at different heat treatment temperatures were characterized by X-ray diffraction, Raman spectrum, scanning electron microscopy, polarized microscopy and vibrating sample magnetometry. The results show that crystals of different substances grow up independently. Cobalt ferrite is evenly embedded into the titanium dioxide matrix in the prepared composite films. The magnetism of the composite films is enhanced with an increase of the heat temperature.  相似文献   

7.
We report the fabrication of β-Ga_2O_3 nanostructures on Au-coated(0001) sapphire substrate by chemical vapor deposition. The morphologies and structural properties of β-Ga_2O_3 nanostructures were characterized by scanning electron microscopy, X-ray diffraction and transmission electron microscopy. Different morphologies including nanowire, nanoflag and nanosheet were controllably synthesized by adjusting the important growth parameters of ambient source contents. It is suggested that the relative ratio of oxygen and gallium contents plays a significant role in determining the morphologies of β-Ga_2O_3 nanostructure.  相似文献   

8.
Cobalt-manganese nano catalysts were prepared by sol-gel method. This research investigated the effects of different cobalt-manganese (Co/Mn = 1/1) loading, pH and calcination conditions on the catalytic performance of Co-Mn/TiO2 catalysts for Fischer-Tropsch synthesis (FTS) in a fixed bed reactor. It was found that the catalyst containing 30wt%(Co-Mn)/TiO2 was an optimal catalyst for the conversion of synthesis gas to light olefins especially propylene. The activity and selectivity of optimal catalyst were studied under different operational conditions. The results showed that the best operational conditions were H2 /CO = 1/1 molar feed ratio at 250℃ and GHSV = 1300 h-1 under atmospheric pressure. Characterization of catalysts was carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption-desorption measurements.  相似文献   

9.
ZnS with hexagonal prism morphology has been synthesized successfully by molten-salt method with ZnS nanoparticles as precursors, and the ZnS nanoparticles were prepared by one-step solid-state reaction of Zn(CH3COO)2·2H2O with Na2S·9H2O at ambient temperature. Crystal structure and morphology of the product were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and HRTEM. Ultraviolet-visible optical absorption spectrum of the ZnS hexagonal prism shows a distinct red shift from that of bulk ZnS crystals and photoluminescence spectrum exhibits strong emissions at 380 and 500 nm, respectively. Further experiments were designed and the formation mechanism of the ZnS hexagonal prism has been also discussed in brief.  相似文献   

10.
STUDY ON THE BLENDS OF NYLON 66 AND LIQUID CRYSTALLINE POLYESTERS   总被引:1,自引:0,他引:1  
Blends of polyamide (Nylon 66) with two different kinds of liquid crystalline polyesters were studied in all the composition range. Homogeneous samples were obtained by coprccipitation from 2 wt%. solution of blends. The thermal properties, crystallinity and morphology of these blends were studied by using DSC, polarizing microscopy, and scanning electron microscopy. The phase transition and morphology of the blends are markedly-influenced by the composition of liquid crystalline polyesters. The mechanical behaviour of PHB/HNA-Nylon 66 blend was improved. although polyamidc (Nylon 66)with the liquid crystalline polyesters were incompatible, but a rather strong interaction between the polymers did exist.  相似文献   

11.
Helical mesoporous silica nanorods were prepared using cetyltrimethylamrnonium bromide and achiral alcohols as the co-structure-directing agents.They were characterized using field-emission scanning electron microscopy,transmission electron microscopy,nitrogen sorptions,and small angle X-ray diffraction.The length of the silica nanorods increases with increasing the length of the alcohols.When n-heptanol and n-octanol were used,helical mesoporous silica nanorods with lamellar mesopores on the surfaces were obtained.  相似文献   

12.
Nanosized Fe-Co catalysts were prepared by co-precipitation method and studied for the conversion of synthesis gas to light olefins.In particular,the effects of a range of preparation variables such as Co/Fe molar ratios of the precipitation solution,pH value of precipitate,temperature of precipitation,promoters and loading of optimum promoter on the structure and catalytic performance are investigated.The optimal nano catalyst for light olefins (C2-C4) production was obtained over the catalyst with Co/Fe molar ratio of 3/1 which promoted with 2 wt% K.The results show that the best operational conditions were GHSV=2200 h-1 (H2/CO=2/1) at 260℃ under atmospheric pressure.Characterization of catalysts were carried out using X-ray diffraction (XRD),thermal gravimetric analysis (TGA),differential scanning calorimetry (DSC),scanning electron microscopy (SEM),transmission electron microscopy (TEM) and N2 physisorption measurements such as Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods.  相似文献   

13.
闫寿科 《高分子科学》2016,34(4):513-522
Oriented thin films of P3HT were obtained by a friction-transfer technique. The morphology and structure of the film were studied by means of optical microscopy, atomic force microscopy and transmission electron microscopy. Optical microscopy observation indicates that large size well-ordered P3HT thin films can be produced by a friction-transfer technique. Highly ordered lamellae were observed in P3HT friction-transferred films by electron microscopy. Electron diffraction results confirm the existence of high orientation with the a- and c-axes of P3HT crystals aligned in the film plane while the c-axis parallel to the friction-transfer direction. The atomic force microscopy observation of the as-prepared P3HT thin film shows, however, a featureless top surface morphology, indicating the structure inhomogeneity of the obtained film. To get highly oriented P3HT thin films with homogenous structure, high temperature annealing, solvent vapor annealing and self-seeding recrystallization of the friction-transferred film were performed. It is confirmed that solvent vapor annealing and self-seeding recrystallization methods are efficient in improving the surface morphology and structure of the frictiontransferred P3HT thin film. Highly oriented P3HT films with unique structure can be obtained through friction-transfer with subsequent solvent vapor annealing and self-seeding recrystallization.  相似文献   

14.
A new type of liquid crystalline polyesters with resorcin as one part of the mesogenic unitconnected together by polymethylene, or phenylene group, and lateral groups consisting of arigid azobenzene as another part of the mesogenic unit were synthesized by interfacialpolymerization of diacyl chlorides in 1, 2-dichloroethane and 2, 4-dihydroxy-4'-nitroazobenzen inaqueous alkaline solution. The polyester structures were confirmed by proton NMR and IRspectra. Their phase transition behavior and texture were studied by polarizing microscopy andDSC.  相似文献   

15.
Nanostructured ZnO and CuO, and coupled oxides, i.e., ZnCu, Zn2Cu, and ZnCu2, with ZnO:CuO molar ratios of 1:1, 2:1, and 1:2, respectively, were successfully prepared through a simple, one-step, mi-crowave-assisted urea–nitrate combustion synthesis, without the use of organic solvents or surfac-tants. The prepared samples were characterized using X-ray diffraction, X-ray photoelectron spec-troscopy, scanning electron microscopy, energy-dispersive X-ray analysis, transmission electron microscopy, Fourier-transform infrared spectroscopy, diffuse reflectance spectroscopy, and photo-luminescence spectroscopy. The optical absorption of ZnO extended into the visible region after CuO loading. The photocatalytic activities of ZnO, CuO, and the coupled oxides were evaluated based on photodegradation of 2,4-dichlorophenol under visible-light irradiation. The coupled metal oxide Zn2Cu showed the best photocatalytic activity;this was mainly attributed to the extended photore-sponsive range and the increased charge separation rate in the nanocomposite. The photocatalytic degradation process obeyed pseudo-first-order kinetics. The results suggest that the coupled metal oxide Zn2Cu has potential applications as an efficient catalytic material with high efficiency and recyclability for the photocatalytic degradation of organic pollutants in aqueous solution under visible-light irradiation.  相似文献   

16.
CdIn2S4 microspheres were synthesized by a facile hydrothermal method with the temperature ranging from 120 to 200 ℃. X-ray diffraction, UV-vis diffuse reflectance spectroscopy, nitrogen sorption analysis, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy were used to characterize the products. It was found that the crystallographic structure and optical property of the products synthesized at different temperature were almost the same. The SBET of CdIn2S4 products decreased when the synthesized temperature increased, and the largest SBET was 33.16m2g-1 (120 ℃ sample). The degradation of methyl orange (MO) under the visible-light irradiation had been used as a probe reaction to investigate the photocatalytic activity of the as-prepared CdIn2S4, which showed that the CdIn2S4 sample synthesized at 120 ℃ presented the best photocatalytic activity for MO degradation.  相似文献   

17.
Fe3O4 nanorods and Fe2O3 nanowires have been synthesized through a simple thermal oxide reaction of Fe with C2H2O4 solution at 200-600℃ for 1 h in the air. The morphology and structure of Fe3O4 nanorods and Fe2O3 nanowires were detected with powder X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The influence of temperature on the morphology development was experimentally investigated. The results show that the polycrystals Fe3O4 nanorods with cubic structure and the av...  相似文献   

18.
Formation and Structure Characterization of Flower-like ZnS Microspheres   总被引:1,自引:0,他引:1  
ZnS nanophases were synthesized through a low-temperature route using a mixed solvent, diethylenetriamine (DETA) and deionized water (DIW), as the reaction medium. The assynthesized products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The experimental results indicate that ZnS nanophase is formed through a phase evolution of ZnS·(DETA)1/2→ ZnS.DETA→ZnS. The ZnS flower-like microspheres sized around 2μm consist of many nanobelts whose structure could be regarded as an alternative admixture of hexagonal wurtzite (WZ) and cubic zinc blende (ZB). The optical absorption measurements demonstrate that the spectral feature of the sample changes with the evolution of the phase structure.  相似文献   

19.
Ball in cage structures of cobalt sulfide have been successfully prepared by a facile one-pot hydrothermal synthesis approach employing Co(NO3)2·6H2O as the cobalt source and S=C(NH2)2 as the sulfur source. The effects of the reaction parameters (volume ratio of distilled water to ethanol, reaction time and reaction temperature) on the morphology and size of the CoS structures were investigated. The synthesized product was characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. It has been confirmed that the volume ratio of distilled water to ethanol played a key role in the formation of the ball in cage structures, and the formation mechanism of the CoS ball in cage structures was also proposed. The electrochemical capacitance performances of the CoS products were studied, and the CoS ball in cage structures show excellent energy storage characteristics.  相似文献   

20.
Nanostructured ZnO and CuO, and coupled oxides, i.e., ZnCu, Zn2Cu, and ZnCu2, with ZnO:CuO molar ratios of 1:1, 2:1, and 1:2, respectively, were successfully prepared through a simple, one-step, microwave-assisted urea–nitrate combustion synthesis, without the use of organic solvents or surfactants. The prepared samples were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, transmission electron microscopy, Fourier-transform infrared spectroscopy, diffuse reflectance spectroscopy, and photoluminescence spectroscopy. The optical absorption of Zn O extended into the visible region after CuO loading. The photocatalytic activities of ZnO, CuO, and the coupled oxides were evaluated based on photodegradation of 2,4-dichlorophenol under visible-light irradiation. The coupled metal oxide Zn2Cu showed the best photocatalytic activity; this was mainly attributed to the extended photoresponsive range and the increased charge separation rate in the nanocomposite. The photocatalytic degradation process obeyed pseudo-first-order kinetics. The results suggest that the coupled metal oxide Zn2Cu has potential applications as an efficient catalytic material with high efficiency and recyclability for the photocatalytic degradation of organic pollutants in aqueous solution under visible-light irradiation.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号