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991.
Well dispersed Fe3O4 nanoparticles with mean size about 160 nm are synthesized by a simple chemical method at atmosphere pressure. The products are characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and Raman spectrum. Electrochemical properties of the as-synthesized Fe3O4 nanoparticles as anode electrodes of lithium ion batteries are studied by conventional charge/discharge tests, showing initial discharge and charge capacities of 1140 mAh g−1 and 1038 mAh g−1 at a current density of 0.1 mA cm−2. The charge and discharge capacities of Fe3O4 electrode decrease along with the increase of cycle number, arriving at minimum values near the 70th cycle. After that, the discharge and charge capacities of Fe3O4 electrode begin to increase along with the increase of cycle number, arriving at 791 and 799 mAh g−1 after 393 cycles. The morphology and size of the electrode after charge and discharge tests are characterized by SEM, which exhibits a large number of dispersive particles with mean size about 150 nm. 相似文献
992.
Xiangyan Wang Lijuan Wan Tao Yu Yong Zhou Jie Guan Zhentao Yu Zhaosheng Li Zhigang Zou 《Materials Chemistry and Physics》2011
The assembly of NiO nanodiscs (namely nanoflowers) as well as the dispersed NiO nanodiscs have been successfully synthesized via the thermal decomposition of Ni(OH)2 obtained from different Ni sources in non-basic solution. The route is environment-friendly. The materials were characterized by X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM) and N2 adsorption–desorption. The porous structures with pore size around 6 nm can be observed on the single NiO disc. The nanoflowers exhibit better performance than nanodiscs in the electrochemical test and water treatment experiments, due to much more available surface areas and spaces formed in the NiO nanoflowers. 相似文献
993.
The electrical conductivity (σ) and thermoelectric power (S) of six newly synthesized high resistivity organic salts, N-(p-R-phenacyl)-1,7-phenanthrolinium bromides (T compounds), were investigated as a function of temperature. 相似文献
994.
Zhenxuan Zhao Hongxing Dai Yucheng Du Jiguang Deng Lei Zhang Fengjuan Shi 《Materials Chemistry and Physics》2011
MgO nano/microparticles with multiple morphologies and porous structures have been fabricated via the surfactant (poly(N-vinyl-2-pyrrolidone, poly(ethylene glycol) (PEG), cetyltrimethylammonium bromide, oleylamine or triblock copolymer P123 or F127) assisted solvo- or hydrothermal route in a dodecylamine or oleic acid solvent. The as-fabricated MgO samples were characterized by means of numerous techniques. It is shown that the obtained MgO samples were single-phase and of cubic in crystal structure; the particle morphology and pore architecture mainly depended upon the surfactant, solvent, and solvo- or hydrothermal temperature adopted. The solvothermal process resulted in polycrystalline MgO, whereas the hydrothermal one gave rise to single-crystalline MgO. Surface areas (8–169 m2 g−1) of the MgO samples derived solvothermally were lower than those (181–204 m2 g−1) of the MgO counterparts derived hydrothermally, with the mesoporous MgO generated after the PEG-assisted hydrothermal treatment at 240 °C for 72 h possessing the highest surface area. CO2 adsorption capacities of the MgO samples were in good agreement with their surface areas, and the mesoporous MgO derived hydrothermally with PEG at 240 °C for 72 h exhibited the largest CO2 uptake (368 μmol g−1) below 350 °C. We believe that such a high low-temperature adsorption capacity renders the mesoporous magnesia material useful in the utilization of acidic gas adsorption. 相似文献
995.
A possibility of synthesizing the SnO2–Au nanocomposite by the successive ionic layer deposition (SILD) method is demonstrated in this article. It is shown that as a result of successive treatments in solutions of Sn(OH)xFyClz and HAuCl4 the SnO2–Au nanocomposite with a Sn/Au ratio varying from 1:1 to 6:1 can be formed on the surface of substrates. It is found that the value of this ratio depends on the concentration of F ions in solution. The gold in the indicated composite is in the metallic state. The growth of the SnO2–Au composite takes place through the formation of 3-D precipitates, which form a continuous film after 13 deposition cycles. As a result, a layer with averaged thickness of up to 20 nm is formed on the surface. Nanocomposite films, even after treatment at an annealing temperature Tan ∼ 600 °C, have finely dispersed structure. The size of the Au clusters incorporated in the SnO2 matrix is in the range from 3 to 15 nm. Gas sensing characteristics of SnO2 films modified by SnO2–Au nanocomposites are discussed as well. It is shown that surface modification by SnO2–Au nanocomposites can be used for improving operating characteristics of conductometric SnO2-based gas sensors. 相似文献
996.
Uniform single-crystalline In(OH)3 hollow microcubes have been synthesized in large quantities via a hydrothermal reaction of InCl3 with NaF and ethylene glycol (EG) at 140–220 °C for 12 h. Porous In2O3 hollow microcubes with a polycrystalline cubic structure can be obtained via calcining In(OH)3 precursors at 400 °C for 2 h in air. Controlled Synthesis of In(OH)3 and In2O3 hollow microcubes with the average edge lengths in the range of 2.0–4.7 μm can be achieved by changing the hydrothermal reaction temperature. The In(OH)3 hollow microcubes were formed via an EG-assisted oriented attachment growth route using HF bubbles as the templates. Photocatalytic activities of the as-synthesized porous In2O3 hollow microcubes were studied at room temperature. The results indicated that the hollow In2O3 nanostructures display high photocatalytic activity in the photodegradation of rhodamine B and methyl orange. 相似文献
997.
Wenshuang Zhang Xinyong Li Qidong Zhao Yang Hou Yu Shen Guohua Chen 《Materials Chemistry and Physics》2011
Uniform α-Fe2O3 nanotubes with small aspect ratio were successfully fabricated by a hydrothermal method. In situ Fourier-transform infrared spectroscopy was used to study the mechanistic details of adsorption and photocatalytic oxidation of naphthalene over theα-Fe2O3 nanotubes. A possible degradation mechanism of naphthalene was proposed. 相似文献
998.
Trivalent/bivalent metal ions doped TiO2 thin films (MxTi1−xO2, M = Cr3+, Fe3+, Ni2+, Co2+, Mn2+ and x = 0.01, 0.05, 0.1, 0.15, 0.2) were deposited on Indium–tin oxide (ITO) coated glass substrates by spin coating technique. X-ray photoelectron spectroscopy (XPS) showed Ti4+ oxidation state of the Ti2p band in the doped p-TiO2. The homogenous MxTi1−xO2 was used to support n-ZnO thin films with thickness ∼40–80 nm and vertically aligned n-ZnO nanorods (NR) with length ∼300 nm and 1.5 μm. Current (I)–voltage (V) characteristics for the Ag/n-ZnO/MxTi1−xO2/ITO/glass assembly showed rectifying behavior with small turn-on voltages (V0) < 1 V. The ideality factor (η) and the resistances in both forward and reverse bias were calculated. The temperature dependence performance of these bipolar devices was performed and variation of the parameters with temperature was studied. 相似文献
999.
M.E. Nicho S. García-Carvajal P.A. Márquez-Aguilar M. Güizado-Rodríguez J. Escalante-García G. Medrano-Baca 《Materials Chemistry and Physics》2011
Polythiophene derivatives with azo chromophore were synthesized via copolymerization of 3-octylthiophene (3OT) and 2-[N-ethyl-N-[4-[(4-nitrophenyl)azo]phenyl]amino]ethyl 3-thienylacetate (3-DRT). This copolymer has interesting optoelectronic properties and a variety of applications such as electrochromic and electronic devices. The polymerization process of 3OT and the functionalized thiophene was carried out via FeCl3 oxidative polymerization. Thin films of poly(3OT-co-3-DRT) copolymer were prepared by spin-coating technique from toluene. FTIR and 1H NMR spectroscopy revealed the presence of chromophore groups in the copolymer chain. Molecular weight and polydispersity of the polymers were measured by size exclusion chromatography. Changes in the surface topography of copolymers were analyzed by atomic force microscopy; the results showed that the copolymers presented some protuberances of variable size unlike the homogeneous granular morphology of P3OT. It is believed that these changes appeared by the incorporation of 3-DRT in the polymer. P3ATs are electrochromic materials that show color change upon oxidation-reduction process. We report that electrochemical characterization of poly(3OT-co-3-DRT) copolymer films synthesized chemically on indium-tin oxide (ITO) glass substrates showed an additional color to the P3OT homopolymer. Optical absorption properties of the polymer films were analyzed in the undoped and doped states and as a function of 3-DRT concentration in the copolymer. The nonlinear optical properties of the copolymers in the undoped and doped states were analyzed by Z-scan technique. The copolymers showed a change of non-linearity sign when the film was doped and results showed that the copolymers have a positive (self-focusing) and negative (self-defocusing) nonlinear optical properties which make them interesting for application as optoelectronic devices. We determined that the nonlinearity of the polymer films was a Kerr type. 相似文献
1000.
Polypyrrole–poly(?-caprolactone) (PPy–PCL) blends were prepared through an in situ deposition technique wherein different amounts of poly(?-caprolactone) were added during the polymerization of pyrrole. Ammonium persulfate was used as an oxidant in the polymerization of polypyrrole (PPy). Compared with pure PPy, the blends showed higher solubility in many organic solvents. The composition and structural characteristics of PPy–PCL were determined by Fourier transform infrared, ultraviolet–visible, and X-ray photoelectron spectroscopic methods. Scanning electron and transmission electron microscopic methods were performed to observe the morphology of the PPy–PCL blends. The temperature-dependent conductivity of the PPy–PCL blends was measured at 300–500 K. The conductivity increased with increasing PCL concentration in the blends, which can be explained by the increased mobility of charge carriers at high PCL concentrations. Based on the temperature dependence of the electrical conductivity, hopping may be the conduction mechanism involved in the PPy–PCL blending process. 相似文献