用X-射线光电子能谱定性和定量分析钴的化学状态

在Ni-MH和Ni-Cd电池制造业中,对钴的价态确定是重要的。高自旋二价钴给出较强的Shake-up伴峰,而三价钴是反磁性的,没有伴峰,由此可以确定钴的价态,并进行定量分析。由实验结果得出下面的经验方程：X%=100（13-20C）/13（C 1）。式中X%是三价钴的百分含量,C是待测样品Co2p1/2Shake-up伴峰与主峰强度之比。此方程可以给出三价钴近似含量。我们从Cop1/2与Shake-up伴峰之间距离或者从伴峰与主峰强度之比,可以鉴别氢氧化亚钴与氧化亚钴。     

Cobalt sorption in silica-pillared clays

Silicon pillared samples were prepared following conventional and microwave irradiation methods. The samples were characterized and tested in cobalt sorption. Ethylenediammine was added before cobalt addition to improve the amount of cobalt retained. The amount of cobalt introduced in the original clay in the presence of ethylenediammine was the highest. In calcined pillared clays the cobalt retention with ethylenediammine was lower (ca. 40%). In all cases the presence of ethylenediammine increased twice the amount of cobalt sorption measured for aqueous solutions.     

Structural features of green cobalt(III) hydroxide

Emission Mössbauer and X-ray absorption XANES/EXAFS spectroscopic techniques are applied to elucidate the structural features of green cobalt(III) hydroxide. A comparative analysis of structurally characterized cobalt(II) and cobalt(III) oxo-compounds shows that the parameters of the local environment of cobalt atoms in green cobalt(III) hydroxide differ substantially from those of its analogues.     

超临界二氧化碳体系中正八面体氧化钴颗粒的生长及其表征

研究了正八面体氧化钴颗粒在超临界二氧化碳体系中的合成过程。在密闭的不锈钢高压反应釜中,1.0 g乙酸钴和12.0 g干冰在450 ℃下,反应12 h后合成粒径大约10 μm的正八面体氧化钴颗粒。通过XRD、 XPS、TEM、 SEM以及拉曼光谱的分析,氧化钴颗粒是由八个{111}面包裹着的正八面体单晶组成。条件实验显示,超临界二氧化碳体系是正八面体氧化钴颗粒合成的充分条件。其生长机理可能是：乙酸钴在超临界二氧化碳体系中的热分解;氧化钴的结晶和定向缓慢生长。在性能方面,初步研究了正八面体氧化钴颗粒在作为锂离子电池电极材料的应用。     

Topochemical synthesis of cobalt oxide-based porous nanostructures for high-performance lithium-ion batteries

Two kinds of topochemical conversion routes from cobalt hydroxide precursors to cobalt oxide-based porous nanostructures are presented: pyrolysis in air and hydrothermal treatment by the Kirkendall diffusion effect. These cobalt hydroxide precursors were synthesized by a simple hydrothermal approach with sodium acetate as mineralizer at 200 °C. Detailed proof indicates that the process of cobalt hydroxide precursor growth is dominated by a nucleation, dissolution, renucleation, growth, and exfoliation mechanism. By the topochemical conversion processes several Co(3)O(4) nanostructures, such as cobalt oxide-coated cobalt hydroxide carbonate nanowires, cobalt oxide nanotubes, hollow cobalt oxide spheres, and porous cobalt oxide nanowires, have been synthesized. The obtained Co(3)O(4) nanostructures have also been evaluated as the anode materials in lithium-ion batteries. It was found that the as-prepared Co(3)O(4) nanostructures exhibited high reversible capacity and good cycle performance due to their porous structure and small size.     

Synthesis and spectral properties of cobalt(II) and cobalt(III) tetraarylporphyrinates

Reactions of 5,10,15,20-tetraphenylporphin, 5,10,15,20-tetra(4′-methoxyphenyl)porphyrin, and 5,10,15,20-tetra(4′-chlorophenyl)porphyrin with cobalt(II) acetate in dimethylformamide were studied by spectrophotometry. The corresponding cobalt(II) porphyrinates were synthesized and identified. The corresponding cobalt porphyrinates in +3 oxidation state were obtained by reaction of cobalt(II) 5,10,15,20-tetraphenylporphyrinate and cobalt(II) 5,10,15,20-tetra(4′-methoxyphenyl)porphyrinate with 2,3-dichloro-5,6-dicyano-p-benzoquinone in chloroform. The oxidation of cobalt(II) 5,10,15,20-tetra(4′-chlorophenyl)porphyrinate with hydrochloric acid in dimethylformamide leads to cobalt(III) porphyrinate.     

Substrate assisted electrochemical deposition of patterned cobalt thin films

The patterned Co layers deposited on the scratched Cu surfaces were investigated with the use of the scanning electron microscopy. Patterned cobalt thin films were electrochemically deposited from the cobalt sulfate bath at room temperature. Pattering of cobalt was carried out by simple means of substrate scratching. Gentle scratching induces a direct pattering of cobalt from vertical to horizontal. The prepared pattered films were characterized for their structural, surface morphological and compositional properties by means of X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. X-ray diffraction studies reveal that the films are of cobalt. From the SEM images fabrication of patterns of cobalt is apparent. This work demonstrates a novel approach for obtaining patterned cobalt for many technological applications.     

Studies on removal of cobalt from an alkaline waste using synthetic calcium hydroxyapatite

The removal of cobalt from an alkaline waste solutions containing sodium was carried out using a radiotracer in a batch method using synthetic calcium hydroxyapatite (HAP). The influence of different parameters such as solution pH, contact time, cobalt concentration, and presence of other ions like sodium on cobalt removal was studied. The sorption process followed pseudo-second-order kinetics with necessary time of around 23–25 h to reach equilibrium and the cobalt uptake was quantitatively evaluated using the Freundlich model. The results indicated that the mechanism of cobalt removal by HAP was mainly due to chemisorption on a heterogeneous surface. In the presence of sodium, the sorption of cobalt on HAP was not affected. The sorption of cobalt on HAP was pH independent in the range from 4 to 8, because of its buffering properties. The adsorption of cobalt on HAP was fast and the percentage of cobalt sorption was >97 % during the first 30–40 min of the contact time.     

Electrochemical studies of azido(imidazole) cobaloxime complexes

Summary Cyclic voltammetric studies of a series of azido(imidazole) cobaloxime complexes in acetonitrile with tetraethylammonium perchlorate as the supporting electrolyte reveal the presence of the central cobalt atom in these complexes in the +III state. In addition to reductions to cobalt(II), cobalt(I) and cobalt(0) species, evidence for oxidation to cobalt(IV) also was noted.     

Comparison of the sorption properties of natural and synthetic zeolites for the purification of aqueous solutions from cobalt: sorption of the cobalt from aqueous solutions in dynamic conditions and the quantitative determination of cobalt by the PIXE method

A methodology of quantitative determination of cobalt using the PIXE method has been developed. The method is based on the use of instant nuclear-physical analysis with the inducement of a target by a 1.6 MeV proton beam and the recording of the characteristic X-ray emission of the K-series of the cobalt. The linear relationship between the quantitative content of cobalt strontium and its X-ray emission K-shell was obtained. The sorption of cobalt by natural and synthetic zeolites from aqueous solutions in dynamic conditions has been studied. Sorption of cobalt with clinoptilolite after 80 cycles of sorption was about 60%. Sorption of cobalt after 80 cycles of sorption by zeolites NaX and NaA was 86 and 70%. Consideration was given to the influence of competing ions (sodium) on the sorption of cobalt by zeolites. The introduction of competing ions leads to a decrease in sorption of the cobalt by 25–60%, depending on the content of competing ions.     

Complexes formed in the chloroform extraction of cobalt(II) with oxine

Absorption spectra of cobalt-oxine complexes-extractedinto chloroform indicate that two cobalt(II) and one cobalt(III) complexes can be extracted depending on pH and the initial concentrations of oxine in the organic phase or cobalt(II) ion in the aqueous phase. The oxidation state of cobalt in the complexes was determined by treatment of organic extracts with an 0.001 M EDTA solution at pH 4–5; cobalt(II) complexes were back-extracted, and the cobalt(III) complex was not. The equilibrium distribution ratios of cobalt(II) between aqueous perchlorate solutions and oxine solutions in chloroform were determined at 20°. A plot of logD_co-log[HO_x]_o vs. pOx gave a single curve for different concentrations of oxine; it was concluded that cobalt(II) is extracted as C_oOx₂HOx.     

Atom states and interatomic interactions in complex perovskite-like oxides: XXVIII. Magnetic dilution in the La(Sr)CoO<Subscript>3</Subscript>-LaGaO<Subscript>3</Subscript> system

Magnetic susceptibility and ESP spectra of lanthanum gallates doped with cobalt and also with cobalt and strontium in the ratio 5:1 were studied. The introduction of strontium results in the formation of cobalt atom clusters including strontium and an oxygen vacancy, cobalt(III) transferring into the high-spin state.     

化学镀钴和超级化学镀填充的研究进展

随着半导体集成度的不断提高,铜互连线的电阻率迅速提高。当互连线宽度接近7 nm时,铜互连线的电阻率与钴接近。IBM和美国半导体公司（ASE）已经使用金属钴取代铜作为下一代互连线材料。然而,钴种子层的形成和超级电镀钴填充7 nm微孔的技术工艺仍是一个很大的挑战。化学镀是在绝缘体表面形成金属种子层的一种非常简单的方法, 通过超级化学镀填充方式, 直径为几纳米的盲孔可以无空洞和无缝隙的方式完全填充。本文综述了化学镀钴的研究进展,并分析了还原剂种类对化学镀钴沉积速率和镀膜质量的影响。同时, 在长期从事超级化学填充研究的基础上, 作者提出了通过超级化学镀钴技术填充7 nm以及一下微盲孔的钴互连线工艺。     

Soft‐Chemical Exfoliation Route to Layered Cobalt Oxide Monolayers and Its Application for Film Deposition and Nanoparticle Synthesis

A colloidal suspension of exfoliated, layered cobalt oxide nanosheets has been synthesized through the intercalation of quaternary tetramethylammonium ions into protonated lithium cobalt oxide. According to atomic force microscopy, exfoliated nanosheets of layered cobalt oxide show a plateau‐like height profile with nanometer‐level height, underscoring the formation of unilamellar 2D nanosheets. The exfoliation of layered cobalt oxide was cross‐confirmed by X‐ray diffraction, UV/Vis spectroscopy, and transmission electron microscopy. The maintenance of the hexagonal in‐plane structure of the cobalt oxide lattice after the exfoliation process was evidenced by selected‐area electron diffraction and Co K‐edge X‐ray absorption near‐edge structure analysis. The zeta‐potential measurements clearly demonstrated the negative surface charge of cobalt oxide nanosheets. Adopting the nanosheets of layered cobalt oxide as a precursor, we were able to prepare the monodisperse CoO nanocrystals with a particle size of ≈10 nm as well as the heterolayered film composed of cobalt oxide monolayer and polycation.     

Dosage electrochimique du cobalt: I. Etude des Courbes Intensité— Potentiel du Système cobalt(III)/cobalt(II) en Milieu Picolique

Electrochemical determination of cobalt. Part I. Studies of current—voltage curves of the cobalt(III)/cobalt(II) system in picolinic acid mediaAs a preliminary to the development of electrochemical determinations of cobalt in steels, current—voltage curves at a platinum electrode were studied for the systems coblt(III)/cobalt(II) and iron(III)/iron(II) in media containing picolinic acid as complexing agent. Iron(III) oxidizes cobalt(II) in this complexmg medium, and the iron-(II) formed can be determined by an oxidant such as cerium(IV).     

Polytypic transformations during the thermal decomposition of cobalt hydroxide and cobalt hydroxynitrate

The isothermal decomposition of cobalt hydroxide and cobalt hydroxynitrate at different intervals of temperature leads to the formation of Co₃O₄. The phase evolution during the decomposition process was monitored using powder X-ray diffraction. The transformation of cobalt hydroxide to cobalt oxide occurs via three phase mixture while cobalt hydroxynitrate to cobalt oxide occurs through a two phase mixture. The nature of the sample and its preparation method controls the decomposition mechanism. The comparison of topotactical relationship between the precursors to the decomposed product has been reported in relation to polytypism.     

Dosage electrochimique du cobalt : II. Applications aux Aciers à Faible ou à Moyenne Teneurs

Electrochemical determination of cobalt. Part I. Studies of current—voltage curves of the cobalt(III)/cobalt(II) system in picolinic acid mediaAs a preliminary to the development of electrochemical determinations of cobalt in steels, current—voltage curves at a platinum electrode were studied for the systems coblt(III)/cobalt(II) and iron(III)/iron(II) in media containing picolinic acid as complexing agent. Iron(III) oxidizes cobalt(II) in this complexmg medium, and the iron-(II) formed can be determined by an oxidant such as cerium(IV).     

Contributions to the basic problems of complexometry-XXI: determination of nickel in the presence of cobalt

A new method for the determination of nickel in the presence of cobalt, based on the masking of the cobalt with potassium cyanide and hydrogen peroxide, is proposed. The yellow, or orange-yellow, complex of cobalt(III) is formed, from which cobalt is not displaced upon the addition of silver nitrate. Tetracyanonickelate, however, reacts quantitatively with silver nitrate, and the displaced nickel can be determined directly with EDTA, using Murexide as indicator. Up to 30 mg of cobalt can be tolerated in the solution.     

Optimal Conditions of Ion-Exchange Synthesis of Cobalt(II) Hydroxide with AV-17-8 Anion Exchanger in the OH Form

Ion-exchange synthesis of cobalt(II) hydroxide by treatment of aqueous solutions of cobalt salts with OH form of AV-17-8 anion exchanger was studied. The influence of time, anion of cobalt salt, number of precipitation stages, and anion exchanger swelling on the degree of cobalt(II) precipitation was examined.     

Coordination compounds of hydrazine derivatives with transition metals,part XVIII. Cobalt(II) and cobalt(III) chelates with schiff bases derived from hydrazine-S-methyldithiocarboxylate and thiosemicarbazide

Summary The reactions of aldehydic and ketonic Schiff bases derived from hydrazine-S-methyl dithiocarboxylate and thiosemicar-bazide with cobalt(II) acetate were investigated. Octahedral tris ligand cobalt(III) chelates were formed with aldehydic Schiff bases whereas tetrahedral bis ligand cobalt (II) chelates were isolated with ketonic Schiff bases.N-isopropylidene hydrazine-S-methyldithiocarboxylate, however, gave both octahedral tris cobalt(III) and tetrahedral bis cobalt(II) chelates. These results are interpreted in terms of the steric requirements of the Schiff base used.