Synthesis and electrochemical performance of β-Co(OH)2

A novel electro-active material was synthesized by precipitation under high levels of supersaturation. The compound was pure β-Co(OH)₂ with hexagonal crystal structure by XRD analysis, and it was flake-shaped, 50–200 nm in particle size and ∼20 nm in thickness by FE-SEM observation. The quasireversible electrochemical reaction between β-Co(OH)₂ and Co upon charging/discharging produced a maximum discharge capacity of 462 mAh g⁻¹, and furthermore the discharge capacity retained 97.6% of the initial capacity at the 100th cycle. These findings highlight the potential for β-Co(OH)₂ compound in applications to negative electrode materials of alkaline rechargeable batteries.     

Microwave-assisted preparation of Ca6Si6O17(OH)2 and β-CaSiO3 nanobelts

Xonotlite (Ca₆Si₆O₁₇(OH)₂) nanobelts were synthesized by a microwave-assisted hydrothermal method at 180 °C for 90 min independent of the feeding molar ratio of Ca(NO₃)₂·4H₂O to Na₂SiO₃·9H₂O in the range of 0.8-3.0. Crystalline wollastonite (β-CaSiO₃) nanobelts were obtained by microwave thermal transformation of Ca₆Si₆O₁₇(OH)₂ nanobelts at 800 °C for 2 h. Ca₆Si₆O₁₇(OH)₂ nanobelts were used as both the precursor and the template for the preparation of β-CaSiO₃ nanobelts. The morphology and size of Ca₆Si₆O₁₇(OH)₂ nanobelts could be well preserved during the microwave thermal transformation process. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and selected area electron diffraction (SAED).     

Crystal structure of uranyl μ3-oxoacetate [(UO2)3(μ3-O)2(OOCCH3)2(H2O)2]

The crystal structure of [(UO₂)₃(₃-O)₂(OOCCH₃)₂(H₂O)₂] consists of uranium coordination polyhedra (CPs) combined via common equatorial edges into ribbons, with ₃-O atoms being common for three CPs. The structure was compared with that of known complexes with ₃-oxo atoms.Translated from Radiokhimiya, Vol. 46, No. 5, 2004, pp. 396–400.Original Russian Text Copyright © 2004 by Charushnikova, Krot, Starikova.     

复合材料Co2（OH）4-x(C10H17O2)x·zH2O的差热分析与磁特性

将有机手性配体3,7-二甲基-6-辛烯酸(C10H18O2)嫁接到无机层状羟基醋酸钴中,合成出新型的有机-无机杂化材料,并对这些杂化材料通过元素和热重分析,研究了有机配体在无机层间的交换过程,并在此基础上讨论了合成出的这些杂化材料的磁性特性。     

Hydrothermal synthesis of ultra fine β-Co(OH)2 nanowires with novel morphologies using supercritical water

Different morphologies of single-crystalline β-cobalt hydroxide (β-Co(OH)₂) nanostructures are successfully synthesized in large quantities by a facile hydrothermal synthetic method with cobalt powder as the cobalt source, supercritical water and triethylamine as both an alkaline and a complexing reagent. This synthetic method has good prospects for the future large-scale production of single-crystalline β-Co(OH)₂ nanostructures owing to its high yield, low cost, and simple reaction apparatus. Ultra fine nanowires, nanowires with branched ultra fine nanoneedle (forest) and nanobelt with branched nanoneedles (pan trees) like structures of cobalt hydroxide are obtained with varying the ratio between supercritical water and triethylamine by 1:0, 2:1 and 1:2, respectively. The obtained morphologies are hexagonal phase of β-cobalt hydroxide with high crystallinity.     

含钛磷酸盐玻璃NaTi2(PO4)3-0.9Ca3(PO4)2的析晶行为

利用差热分析、X射线衍射仪、液氮吸附BET孔经测试仪对组成为NaTi2(PO4)3-0.9 Ca3(PO4)2的含钛磷酸盐玻璃的析晶行为进行了研究.通过对该玻璃相继进行成核、析晶和酸浸泡处理制备了NaTi2(PO4)3骨架多孔微晶玻璃.证明该玻璃在646℃8h成核处理过程中产生了旋节分解特征的成分偏聚,形成了富TiO2玻璃相和富CaO玻璃相交错生长的连通结构,成核处理后的玻璃在738℃析晶过程中依次在富钛相和富钙相中析出NaTi2(PO4)3和β-Ca3(PO4)2.成核过程对析晶的促进作用是通过促进NaTi2(PO4)3的析出而实现的.     

Self-propagating high-temperature synthesis of Y2O3 powders from Y(NO3)3x(CH3COO)3(1 ? x) · nH2O

We have studied the self-propagating high-temperature synthesis (SHS) of yttrium oxide from Y(NO₃)_3x (CH₃COO)_{3(1 − x)} · nH₂O (0.3 ≤ x ≤ 0.7) acetate nitrates, calculated their standard enthalpies of formation using the method of valence states of atoms in a chemical compound, and compared calculated and experimentally determined yttrium oxide SHS temperatures. Using thermogravimetry and differential scanning calorimetry data and thermodynamic analysis, we have determined the optimal range of yttrium acetate nitrate compositions for the SHS of Y₂O₃ powder.     

FeVO4/Cu3(BTC)2(H2O)3异质结制备及光催化性能

以Cu片和1, 3, 5-苯三甲酸为原料,电化学法制备经典Cu-MOF材料Cu₃(BTC)₂(H₂O)₃,即HKUST-1,作为基底金属有机框架材料(MOFs),采用室温沉积法制备FeVO₄/HKUST-1异质结复合材料,通过XRD、SEM、BET、UV-Vis DRS等对其晶体结构、形貌、比表面积、光吸收性能等进行了表征。结果表明:FeVO₄与HKUST-1复合形成异质结后,有利于光生电子-空穴的产生和转移,对目标染料污染物罗丹明B(RhB)的降解性能显著增强。可见光照射120 min后,异质结体系中RhB的降解率可达93%,而单一FeVO₄或HKUST-1体系中仅为12%和5%。此外,对材料的组成比例进行了优化,当FeVO₄与HKUST-1摩尔比为1∶1时,制备的FeVO₄/HKUST-1复合材料具有最佳的光催化性能。进一步,考察了其循环使用的稳定性,循环5次后对RhB的降解效率仍保持在90%以上,稳定性良好。      

高效温和制备纳米片状β-Co(OH)2用于超级电容器电极

以水合氯化钴为原料,氢氧化钠和水合肼为碱性沉淀剂,在不添加任何分散剂的情况下采用化学沉淀法制备出呈六边形的片状β-Co(OH)_2。采用X射线衍射和透射电子显微镜表征所制样品的结构和形貌,采用循环伏安和恒电流充放电等测试方法对其电化学性能进行初步研究。结果表明,六边形片状β-Co(OH)_2边长为100~200nm,厚度为几十纳米,且随氯化钴溶液浓度的降低,单晶片的厚度逐渐减小。其表现出一定的电化学性能,电流密度为1A/g时,比电容可达到83.3F/g,且性能稳定。     

Elastic and inelastic properties of (Co0.45Fe0.45Zr0.1) x (Al2O3)1 ? x nanocomposites

The elastic (Young’s modulus) and inelastic (internal friction) properties of amorphous (Co₄₅Fe₄₅Zr₁₀) _x (Al₂O₃)_{100 − x} nanocomposites with various relative contents of the metallic and dielectric phases have been studied. In the region of low temperatures, the composites exhibit a peak of the internal friction (at ∼240 K), the intensity of which increases with the content of the metallic phase. For compositions above the percolation threshold, the temperature dependence of the internal friction exhibits exponential growth above 300°C, which is related to the migration of vacancy-like defects in the amorphous structure of the metallic phase.     

Co3O4纳米颗粒的制备及表征

以脱脂棉为碳源,硝酸钴为前驱物,采用碳辅助法焙烧制备了粒径为50nm Co3O4纳米颗粒。用X射线衍射(XRD)对不同焙烧温度(200~600℃)下样品的物相、晶粒度进行了研究,并结合傅立叶红外光谱(FT-IR)对Co3O4物相演变进行了分析,确定中间产物前躯体是CoCO3;通过扫描电镜(SEM)和透射电镜(TEM)对制备的Co3O4样品的形貌、粒径进行了分析;同时,X射线能谱(EDS)和氮气吸附-脱附曲线测试等表明制备的Co3O4表面存在碳元素和孔结构,具有较大的比表面积,有利于提升其光解水制氢能力。     

Er2O3掺杂Gd2(Zr0.8Ti0.2)2O7陶瓷的物理性能

用固相反应法制备(Gd_1-xEr_x)₂(Zr_0.8Ti_0.2)₂O₇(摩尔分数x=0,0.2,0.4)陶瓷并测试其晶体结构、显微形貌和物理性能,研究了Er₂O₃掺杂的影响。结果表明,(Gd_1-xEr_x)₂(Zr_0.8Ti_0.2)₂O₇陶瓷具有立方烧绿石结构,显微结构致密,在室温至1200℃高温相的稳定性良好;Er³⁺掺杂降低了陶瓷材料的热导率和平均热膨胀系数,当x=0.2时,其1000℃的热导率最低(为1.26 W·m^-1·k^-1)。同时,Er³⁺掺杂还提高了这种材料的硬度和断裂韧性。     

过硫酸氢盐催化材料(Co3O4/ACF)的制备及应用

通过改变溶剂热法和水热法中材料的配比和温度制备了18种四氧化三钴/活性炭纤维(Co₃O₄/ACF)复合材料,并将这些复合材料用于催化过一硫酸盐(PMS)降解染料橙黄Ⅱ。考察了制备材料的配比(Co²⁺和ACF)和温度对制得的Co₃O₄/ACF复合材料催化降解橙黄Ⅱ效率的影响,并采用X射线衍射仪、扫描电镜等对复合材料的元素组成和形貌进行了表征。结果表明:水热法制得的复合材料催化性能好,3 min内可完全降解100 mg/L橙黄Ⅱ。从表征结果可见,水热法能更有效地使Co₃O₄颗粒以纳米尺寸分散负载在ACF上。材料的配比对产品的催化降解效率无显著影响,温度对水热法制得的产品的催化降解效率影响不大。水热法在320 ℃条件下煅烧制得的复合材料催化性能好且ACF能基本保持结构完整,Co负载量约为17.2 mg/g。水热法制备的Co₃O₄/ACF复合材料循环利用性能优于溶剂热法制得的材料,在循环使用四次后,28 min内橙黄Ⅱ降解效率仍能达到99%。其高效降解与Co₃O₄/ACF和溶解态Co²⁺的催化作用均有关。正交试验表明,降解过程中时间对降解效果的影响最大,其次是PMS的浓度,催化材料的加入量对降解效率无明显影响。因此,在复合材料应用中,应保证充足的降解时间,并适当提高PMS的浓度。     

苯胺-SrTi(C2O4)2颗粒制备及其电流变性能

用沉淀法制备了苯胺-草酸氧钛锶（SrTi（C₂O₄）₂）颗粒。FTIR分析表明,苯胺已引入到SrTi（C₂O₄）₂颗粒的表面;XRD分析表明,苯胺-SrTi（C₂O₄）₂颗粒为含少量结晶的无定形态。采用SEM观察颗粒的形貌,结果表明,随反应体系中苯胺与钛原子物质的量比n_aniline/n_Ti的增大,苯胺-SrTi（C₂O₄）₂颗粒由近似球状（n_aniline/n_Ti =0）变为多面体状（n_aniline/n_Ti =2）,而后变为棒状与团簇状颗粒的混合体系（n_aniline/n_Ti =3）。以苯胺-SrTi（C₂O₄）₂颗粒为分散相制备颗粒质量分数为66.7%电流变液,电流变性能测试结果表明,在n_aniline/n_Ti =2时,电流变液具有较高的剪切应力和剪切屈服强度、较大的漏电流密度。苯胺在颗粒制备过程中起控制颗粒形貌的作用,在电流变液体系中起极性分子的作用,其对苯胺-SrTi（C₂O₄）₂电流变液性能的影响是两种效应综合作用的结果。     

Photoluminescence properties of β-Ga2O3:Tb nanofibers prepared by electrospinning

One-dimensional Tb³⁺-doped β-Ga₂O₃ nanofibers were prepared by a simple and cost-effective electrospinning process. Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Raman technique, and photoluminescence (PL) were used to characterize the electrospun nanofibers. FE-SEM results indicated that the diameters all of the nanofibers ranged from 100 to 300 nm, and the lengths of nanofibers reached up to several millimeters. The XRD and Raman results showed that the Ga₂O₃ phase belongs to the monoclinic phase. Under ultraviolet excitation, the β-Ga₂O₃:Tb³⁺ samples showed green emission with the strongest peak at 550 nm, corresponding to ⁵D₄ → ⁷F₅ transition of Tb³⁺ ions. The luminescence intensity had been further studied as a function of the doping concentration of Tb³⁺ in the β-Ga₂O₃ samples.     

Existence of a solid solution from brucite to β-Co(OH)2

This study shows that between brucite (Mg(OH)₂) and β-Co(OH)₂, all the compositions are possible. The solid solution Mg_1?xCo_x(OH)₂ has been synthesized by an easy and fast coprecipitation route and characterized by XRD and TEM. Single phase powders have been obtained. The particles exhibit platelets morphology with a size close to one hundred nanometers. XRD analysis shows an evolution of the cell parameters when x increases and demonstrates that no ordering of the cations occurs. However, extra reflections on TEM electron diffraction patterns seem to indicate that local ordering can exist. The compounds issued from this solid solution could be good candidates as precursors in order to obtain Mg–Co mixed oxide with all possible cationic ratios.     

Multifunctional γ-Fe2O3@Ca3(PO4)2@YPO4:Tb,Ce nanocomposites as a potential drug carrier

Multifunctional γ-Fe₂O₃@Ca₃(PO₄)₂@YPO₄:Tb³⁺,Ce³⁺ nanocomposites were synthesized using an easy direct-precipitation method. The nanocomposites had a monodispersed spherical morphology with a narrow size distribution, and dispersed well in water. The nanocomposites showed the characteristic emission peaks of Ce³⁺ (5d–4f) and Tb³⁺ (⁵D₄–⁷F₃ to ⁵D₄–⁷F₆). Magnetism measurements revealed that the samples were nearly superparamagnetic. The multifunctional nanocomposites were used for in vitro drug delivery tests under ambient conditions, and we discuss the influence of different media on the release of cisplatin (cis-diamminedichloroplatinum). We assessed the loading and release performance for cisplatin by means of UV–visible spectrophotometry. Our findings will provide guidance for engineering similar multifunctional nanocomposites for use in future drug delivery applications.     

Co3O4/碳复合超级电容器材料的研究进展

Co₃O₄作为超级电容器材料,因具有理论比容量高、价格成本低、无毒环保、储量丰富等优点而备受关注,但制备出电化学性能优异的Co₃O₄超级电容器材料仍是个巨大的挑战。通过与导电性突出的碳材料复合,增加了电子/离子的传输速度,提高了Co₃O₄超级电容器材料电化学性能。综述了Co₃O₄/碳复合超级电容器材料的合成方法,归纳了各个方法的优缺点,分析了影响Co₃O₄/碳复合超级电容器电化学性能的因素,最后,指出了Co₃O₄/碳复合超级电极材料所面临的问题和发展前景。     

纳米微孔杂多化合物Na[Fe2(O2H3)Mo2O8](Ⅰ)和(NH4)[Fe(MoO4)2](Ⅱ)的结构特征

通过采用水热合成法得到了二种具有纳米筛孔的氧簇化合物Na[Fe2(O2H3)Mo2O8](Ⅰ)和(NH4)[Fe(Mo O4)2](Ⅱ).晶体(Ⅰ)属于单斜晶系,空间群为C2/m,晶胞参数为a=9.5450(17),b=6.4381(9),c=0.76405(12)nm;β=116.128(4),Z=2,R1=0.0219,Rw=0.0756.晶体(Ⅱ)属于正交晶系,空间群为Pnma,晶胞参数为a=1.4782(3),b=0.56774(11),c=0.87653(18)nm;Z=4,R1=0.0212,Rw=0.0513.