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91.
Cubic Co3O4 nanocrystals (NCs) were synthesized by a one-pot hydrothermal reaction in the presence of the oxidant KClO3 and the capping reagent polyvinylpyrrolidone (PVP). The as-prepared Co3O4 NCs were uniformly cubic with sharp edges and good crystallinity and showed flat surfaces with {100} facets. The capped PVP could be removed without losing cubic shape by heating the NCs at 300 °C. 相似文献
92.
Jose García-Torres Elvira Gómez Elisa Vallés 《Journal of Applied Electrochemistry》2009,39(2):233-240
Cobalt electrodeposits were prepared from an electrolytic bath containing cobalt perchlorate. The effect of different species,
organic (thiourea and sodium gluconate) and inorganic (boric acid), on the crystallographic structure, morphology, magnetic
properties and electrochemical behaviour of cobalt electrodeposits was investigated. Amorphous cobalt, hcp cobalt and a non-usual
primitive cubic cobalt phase were observed depending on the bath composition. Depending on the structure, different morphologies
and magnetic properties were found. Coercivity values of the cobalt coatings ranged from around 15 Oe for amorphous, nodular
deposits to 380 Oe for cobalt coatings showing acicular morphology and hcp structure with a (002) preferred orientation. Knowledge
of the influence of the species on the properties of cobalt makes it possible to obtain tailored cobalt films. 相似文献
93.
Aasif A. Dabbawala Jaydeep N. Parmar Raksh V. Jasra Hari C. Bajaj Eric Monflier 《Catalysis communications》2009,10(14):1808-1812
The cobalt catalyzed hydroformylation of higher olefins in the presence of chemically modified cyclodextrins was investigated in an aqueous biphasic system. The effect of various parameters, such as the nature of the cyclodextrin and olefin, the temperature, the CO/H2 pressure, the concentration of the cyclodextrin and TPPTS was studied. The results demonstrate that the partially methylated β-cyclodextrin gives good conversion (>92%) and selectivity (>92%) for the hydroformylation of higher olefins without impeding the recovery of the catalytic system. 相似文献
94.
The cobalt electrodissolution process in carbonate-bicarbonate containing solutions 8.9 ? pH ? 10.5 covering relatively wide ranges of ionic strength, pH, and hydrodynamic conditions, has been investigated using electrochemical impedance spectroscopy (EIS) and steady polarization data. To distinguish the competing stages of the metal electrodissolution mechanism a cobalt rotating disc electrode was utilized. The proposed mechanism model consists of the formation of adsorbed Co(I) intermediate species followed by mass-transport contributions of soluble Co(II) ions as final products. The coherence of the proposed mechanisms with EIS and steady polarization data is presented. 相似文献
95.
Nickel was selectively leached from an industrial nickel-cobalt Mixed Hydroxide Precipitate (MHP) under mildly acidic, strongly oxidizing conditions. The resulting cobalt rich residues contained 14-21 wt.% Ni, 3-7 wt.% Co and 3-9 wt.% Mn. The selective extraction of nickel and cobalt from these residues was studied using weak acid and weak acid-reductive leaching. Without the reducing agent, nickel preferentially leached. The controlled addition of a reducing agent increased the extent of nickel leaching and solubilised a portion of the cobalt while manganese remained stable in the solid phase. The extent of copper, iron and aluminium leaching was controlled by pH adjustment. 相似文献
96.
M. B. J. G. Freitas E. M. Garcia V. G. Celante 《Journal of Applied Electrochemistry》2009,39(5):601-607
In this work, cobalt from spent Li-ion batteries of cellular phones was recycled using electrochemical techniques. The efficiency,
structure and morphology of deposits were influenced by the pH solution and charge density. Maximum efficiency is obtained
for pH = 5.40 for all charge densities analyzed. The presence of the cobalt hcp phase for both pH solutions (5.40 and 2.70)
and charge density conditions (10.0 and 50.0 C cm−2) used in the electrodeposition process was detected by X-ray diffraction. The growth of the cobalt deposit is favored in
the crystallographic direction [002] for pH = 5.40 and in the direction [110] for pH = 2.70 when the charge density is 10.0 C cm−2. The [100] and [101] crystallographic directions of hcp phase were detected by X-ray diffractogram for both pH conditions
when the charge density was increased to 50.0 C cm−2. The potentiodynamic dissolution of the cobalt depends on its structural composition. 相似文献
97.
We report on the magnetoelectric characterization of epitaxial CoFe2O4-BaTiO3 nanocomposites grown by rf sputtering on Nb-doped SrTiO3 (001). Multiferroicity of the material is corroborated with both, ferroelectric and ferromagnetic hysteresis loops. Magnetoelectric coupling is investigated via magnetocapacitance measurements; a change of the capacitance of about 2% is observed for an applied magnetic field of 8 T. The possible origins of this magnetocapacitance are discussed. 相似文献
98.
钴与其它金属的复合物对不饱和聚酯固化的促进作用 总被引:2,自引:0,他引:2
研究了钴与碱金属、碱土金属、过渡金属的复合物地不饱和聚酯树脂固化的促进作用,结果令人满意。 相似文献
99.
Torbj rn Vr lstad Gisle
ye Magnus R nning Wilhelm R. Glomm Michael St cker Johan Sj blom 《Microporous and mesoporous materials》2005,80(1-3):291-300
Co-MCM-41 and Co-MCM-48 with cobalt amounts from about 3 wt.% to 9 wt.% have been synthesized under various conditions, and the samples were characterized by XRF, XRD and N2-sorption. EXAFS least-squares curve fitting detected only oxygen and silicon backscattering shells, which verified the incorporation of cobalt into the silica framework both for as-synthesized and calcined samples. XANES profiles showed that the oxidation state of cobalt in the samples is unaltered during synthesis. It has been shown that the cobalt is precipitated as cobalt hydroxide during synthesis, and this hydroxide is in equilibrium with aqueous cobalt ions in the synthesis gel. The precipitated cobalt hydroxide precursors are incorporated into the mesoporous silica framework, while the aqueous cobalt ions remain dissolved in the aqueous phase. The cobalt amount in the final samples is therefore pH dependent. This equilibrium is also important in the formation of the mesoporous structure. Addition of increasing amounts of cobalt salt to a MCM-48 synthesis gel causes a change in the mesoporous structure from cubic Ia3d to hexagonal, which is suggested to be a consequence of the charge density matching process. The increased amounts of the divalent cobalt(II) ions in the gel screen the negatively charged silica precursors, which decreases the total surface charge density of the silica, and thus causes the surfactants to self-assemble into the hexagonal structure. 相似文献
100.
Qing-Xiang Liu Xiao-Jun Zhao Xiu-Mei Wu Su-Wen Liu Yan Zang Shu-Sheng Ge Xiu-Guang Wang Jian-Hua Guo 《Inorganic chemistry communications》2008,11(7):809-813
The two Cd(II) and Co(II) 2-D frameworks have been prepared by means of self-assemblies of Cd(II) or Co(II) salts and 1-substituted imidazole and terephthalic acid, and structurally characterized by X-ray diffraction analyses. In complex 1 2-D frameworks with rhombic cavity are formed, in which the each top point of rhombus contains one hexa and two heptacoordinated Cd(II). In complex 2 2-D networks with rectangular cavities are formed, and the opposite benzene rings from carboxyls in each rectangular cavity are parallel. 相似文献