锌酸钙负极材料的水热法制备及其性能研究

采用水热法,合成了锌酸钙电极材料,制备成电极并组装成模拟锌镍电池．采用X射线衍射、扫描电子显微镜、热重分析、粒度分析、红外光谱以及模拟电池的充放电等方法,对制备出的样品进行了表征．结果表明该方法制备的锌酸钙具有不规则的晶形、较小的粒径和较少的结晶水．模拟锌镍电池的充放电实验表明该样品材料具有良好的电极材料性能：以该锌酸钙为负极活性物质的模拟锌镍电池具有较低的充电电压、较高的放电平台和优良的循环性能．     

Silica gel-polyethylene glycol as a new adsorbent for solid phase extraction of cobalt and nickel and determination by flame atomic absorption spectrometry

In this paper a novel solid phase extraction method to determine Co(II) and Ni(II) using silica gel-polyethylene glycol (Silica-PEG) as a new adsorbent is described. The method is based on the adsorption of cobalt and nickel ions in alkaline media on polyethylene glycol-silica gel in a mini-column, elution with nitric acid and determination by flame atomic absorption spectrometry. The adsorption conditions such as NaOH concentration, sample volume and amount of adsorbent were optimized in order to achieve highest sensitivity. The calibration graph was linear in the range of 0.5-200.0 ng mL⁻¹ for Co(II) and 2.0-100.0 ng mL⁻¹ for Ni(II) in the initial solution. The limit of detection based on 3S_b was 0.37 ng mL⁻¹ for Co(II) and 0.71 ng mL⁻¹ for Ni(II). The relative standard deviations (R.S.D.) for ten replicate measurements of 40 ng mL⁻¹ of Co(II), and Ni(II) were 3.24 and 3.13%, respectively. The method was applied to determine Co(II) and Ni(II) in black tea, rice flour, sesame seeds, tap water and river water samples.     

磷含量对NiMo/γ-Al2O3催化剂活性相结构的影响

采用程序升温还原（TPR）、高分辨透射电镜（HRTEM）和X射线光电子能谱（XPS）表征手段对共浸渍法制备的不同磷含量NiMo/γ-Al₂O₃催化剂进行了表征,研究了磷含量对NiMo/γ-Al₂O₃催化剂活性相结构的影响。TPR研究表明,磷能够减少四面体配位Mo物种的数量,增加八面体配位Mo物种的数量,促进高活性Ⅱ型"Ni-Mo-S"活性相的形成。HRTEM研究表明,随磷含量的增加,MoS₂颗粒堆积层数增加,催化剂的加氢选择性提高;适量磷能够增加边角位有效Mo原子的分散度(fMo),增加催化剂表面加氢脱硫（HDS）和加氢脱氮（HDN）活性位的数量。上述结论得到了XPS表征的证实：适量磷增加了催化剂表面Mo原子浓度、提高有效助剂比率（PR）和提升比率（Ni/Mo）,相应催化剂表现出最高的HDS和HDN活性;但过高磷含量能够引起MoS₂颗粒过度堆积,片层长度过长,导致活性位数量减少,催化活性降低。     

Synthesis and characterization of Co(II), Ni(II), Zn(II) and Cu(II) complexes with a new tetraazamacrocyclic Schiff base ligand containing a piperazine moiety: X-ray crystal structure determination of the Co(II) complex

Two macrocyclic Schiff base ligands, L¹ [1+1] and L² [2+2], have been obtained in a one-pot cyclocondensation of 1,4-bis(2-formylphenyl)piperazine and 1,3-diaminopropane. Unfortunately, because of the low solubility of both ligands, their separation was unsuccessful. In the direct reaction of these mixed ligands (L¹ and L²) and the appropriate metal ions only [CoL¹(NO₃)]ClO₄, [NiL¹](ClO₄)₂, [CuL¹](ClO₄)₂ and [ZnL¹(NO₃)]ClO₄ complexes have been isolated. All the complexes were characterized by elemental analyses, IR, FAB-MS, conductivity measurements and in the case of the [ZnL¹(NO₃)]ClO₄ complex with NMR spectroscopy.     

A formate bridged Ni(II) sheet and its 3D analogue in presence of a linear organic linker: Synthesis,crystal structure and magnetic properties

Reaction of formamide with Ni(NO₃)₂·6H₂O under hydrothermal condition in a mixture of MeOH/H₂O forms a two-dimensional formate bridged sheet Ni(HCOO)₂(MeOH)₂ (1). X-ray structure analysis reveals the conversion of formamide to formate which acts as a bridging ligand in complex 1 where the axial sites of Ni(II) are occupied by methanol used as a solvent. An analogous reaction in presence of 4,4′-bipyridyl (4,4′-bipy) yielded a three-dimensional structure Ni(HCOO)₂(4,4′-bpy) (2). DC magnetic measurements as a function of temperature and field established the presence of spontaneous magnetization with T_c (Curie temperature) = 17 and 20.8 K in 1 and 2, respectively, which can be attributed due to spin-canting. DFT calculations were performed to corroborate the magnetic results of 1 and 2.     

Anisotropy and magnetic properties of the bimetallic thiocyanate-bridged chains: Density-matrix renormalization approach

Magnetic properties of bimetallic thiocyanate-bridged chains are numerically analyzed on the basis of the one-dimensional quantum anisotropic Heisenberg model without the mean-field corrections. The single-ion and g factor anisotropy of the metal ions (Co(II), Mn(II), Ni(II)) are taken into account. The thermodynamic properties are calculated using the DMRG technique, which is reliable in the entire temperature region, adapted to the molecular-based chains. The high accuracy results of our simulations are successfully fitted to the corresponding experimental susceptibility and magnetization data measured for a powder sample. Our analysis permitted determination of the microscopic parameters (the strength of magnetic couplings between the copper and metal ions and the single-ion anisotropy terms) as well as the corresponding g factors which are consistent with the values known for other compounds.     

Syngas production by combined carbon dioxide reforming and partial oxidation of methane over Ni/α-Al2O3 catalysts

Ni/α-Al2O3 catalysts were found to be active in the temperature range 600~900 ℃ for both CO2 reforming and partial oxidation of methane. The effects of Ni loading, reaction temperature and feed gas ratio for the combination of CO2 reforming and partial oxidation of CH4 over Ni/α-Al2O3 were investigated. Catalysts of xwt%Ni/α-Al2O3 (x = 2.5, 5, 8 and 12) were prepared by wet impregnating the calcined support with a solution of nickel nitrate. XRD patterns and activity tests have verified that the 5wt%Ni/α-Al2O3 was the most active catalyst, as compared with the other prepared catalyst samples. An increase of the Ni loading to more than 5 wt% led to a reduction in the Ni dispersion. In addition, by combining the endothermic carbon dioxide reforming reaction with the exothermic partial oxidation reaction, the loss of catalyst activity with time on stream was reduced with the amount of oxygen added to the feed.     

片状镍粉填充树脂基和石蜡基复合材料的微波电磁特性

以微米镍粉作为原料,采用湿法研磨法制备了片状镍粉,将其作为填料用于制备树脂基导电复合材料和石蜡基复合材料;测定了树脂基复合材料的电磁屏蔽性能与镍粉含量的关系,同时考察了片状镍粉/石蜡复合材料的吸波性能.结果表明,复合材料电磁屏蔽性能(SE)随着填料含量的增加而提高;厚度为5 mm的片状镍粉/石蜡复合材料在2 GHz附近的最小反射率可达-27 dB.这表明所制备的片状镍粉在电磁屏蔽及吸波领域具有很好的应用前景.     

二癸基次膦酸的合成及其萃取性能

以廉价的工业副产物混合癸烯和次膦酸钠反应,在常压下合成了二癸基次膦酸,分离产率达99.8%,产物纯度98%.萃取实验表明,二癸基次膦酸对镍/钴分离的选择性要好于Cyanex272,对镍和钴的萃取率和反萃率均大于96%;同时,对钴等金属离子,可实现对低pH浸出液的直接萃取.     

Investigation of radionuclide 63Ni(II) sequestration mechanisms on mordenite by batch and EXAFS spectroscopy study

The sorption behavior and microscopic sequestration mechanisms of radionuclide 63Ni(II) on mordenite as a function of aging time,ionic strength,initial 63Ni(Ⅱ) concentrations,solid content and coexistent electrolyte ions were investigated by the com-bination of batch and EXAFS techniques.Macroscopic experiment results show that the sorption of 63Ni(Ⅱ) is dependent on ionic strength at pH<7,and independent of ionic strength at pH>7.The sorption percentage of 63Ni(Ⅱ) on mordenite increases with increasing solid content,while the sorption capacity decreases as solid content increases.The presence of different elec-trolyte ions can enhance or inhibit the sorption of Ni(II) on mordenite in various degrees.EXAFS analysis results of the sam-ples under three different ionic strengths suggest that the retained 63Ni(Ⅱ) in these samples exists in an octahedral environment with six water ligands.In the initial period of rapid uptake,the sorption of 63Ni(Ⅱ) is dominated by the formation of in-ner-sphere surface complexes.As aging time increases,63Ni(Ⅱ) sequestration behavior tends to be mainly controlled by the formation of Ni phyllosilicate co-precipitates and/or Ni(OH)2(s) precipitates.Results for the second shell fit of the sample pre-pared at an initial 63Ni(Ⅱ) concentration of 100 mg/L indicate the possible formation of Ni polynuclear surface complexes.Both the macroscopic sorption data and the molecular level evidence of 63Ni(Ⅱ) surface speciation at the mordenite/water in-terfaces should be factored into better predictions of the mobility and bioavailability of 63Ni(Ⅱ) in environment mediums.