氢氧化镍纳米晶的水热合成和结构表征

用水热法在180℃合成了非球形的Ni(OH)2纳米晶,并用X射线衍射(XRD)、傅立叶变换红外光谱(FT-IR)、透射电镜(TEM)和高分辨透射电镜(HRTEM)等技术对其形貌和结构作了表征. 结果表明,Ni(OH)2纳米晶的生长习性和形貌都强烈依赖于前驱物溶液的pH值. 在较高的pH值(13.40)下,产物主要是六角片状粒子,而在近中性条件(7.80)下,产物主要是不规则形貌的粒子. 在pH值较高的条件下,除了通常的Ostwald ripening 晶体生长粗化机理外,合并生长机理对纳米晶生长过程也发挥了作用.     

反向沉淀法制备纳米Mg(OH)2阻燃剂的研究

介绍了反向沉淀法制备纳米Mg(OH)2的原理和方法.本方法回避了正向沉淀法中要经过的等电点区间,使制备过程中生成的沉淀微粒始终带有相同的电荷,ξ电位具有相同的符号,有效的防止了沉淀微粒间的凝集.对影响粒径的多种因素进行了分析讨论,提出了解决的办法.     

A novel method for preparing gradient index (GI) plastic rods

Summary The initiator diffusion technique was used in this study to prepare the gradient index(GI) plastic rods, in which two kinds of initiators were used, i.e., thermal initiator and redox initiator. Experimental results showed that a GI plastic rod with a parabolic profile of refractive index was obtained by the initiator diffusion technique. The difference of the refractive index from the center to the periphery (n) of the plastic rods was in the range of 0.004–0.014. n increased with increasing temperature due to the increase of the gel effect and diffusion rates of monomers at a higher temperature. Furthermore, the GI plastic rod had substantially less defects, e.g., bubbles and opaqueness, than that prepared from interfacial-gel copolymerization.     

A simple method for preparing ThO2 ceramics with high density

A simple and effective method for preparing ThO₂ ceramics with high density has been proposed. It mainly includes a positive precipitation approach and a conventional sintering process. The SEM images and laser particle size analysis show that the prepared powder exhibits a round-plated shape with a uniform and narrow particle size distribution, which is the key to the densification sintering of ThO₂ ceramics. The XRD analyses confirm that the ThO₂ ceramics sintered at 1590°C were composed of cubic fluorite phase. The effect of sintering temperature on the density of ThO₂ ceramics was also investigated, and a relative density higher than 95% were achieved after sintering at 1590°C for 6 h in an air atmosphere. Moreover, the Vickers hardness was up to 8.49 GPa, the average linear expansion coefficient within 40–800°C was low to 10.97 × 10⁻⁶/K, and the thermal conductivity and the thermal diffusivity were both higher than most of traditional ceramic materials (16.94–5.86 W/m K and 7.28–1.28 mm²/s, respectively, within the temperature range of 25–800°C). The previous great performances are closely related to its high density, which enables it to be a great candidate for nuclear fuels and other potential application fields.     

5-溴吡啶偶氮-H的合成及应用研究

报道了新试剂 5 -溴吡啶偶氮 -H的合成方法及其与 Cu2 + 显色反应的条件。实验表明 :在弱酸性溶液中 Cu2 + 与试剂形成蓝色配合物 ,K=8.0× 1 0 7,ε=2 .5× 1 0 4L· mol- 1· cm- 1。试剂选择性好 ,应用于岩石矿样中微量铜的测定 ,结果满意     

一种合成水溶性酚醛树脂的简单方法

找到一种简单的合成工艺,并分别考察了原料配比、催化剂用量、反应时间等各种反应条件对产物粘度的影响,得出了用一步法可以生成水溶性酚醛树脂的结论,并找出最佳的反应条件。     

A novel method for preparing bipolar membranes

A method for preparing a bipolar membrane from separate anion and cation exchange films is described. In the procedure an inorganic electrolyte solution is introduced between the films before they are pressed together. The resulting membrane has a low electrical resistance and a high “water splitting” efficiency.     

氢氧化镍纳米片的制备

以硝酸镍为镍源,采用水热法制备N i(OH)2纳米片,通过改变反应物浓度、反应时间、反应温度,研究不同实验条件对N i(OH)2纳米片的影响;通过X-射线衍射、扫描电子显微镜等手段对样品进行了表征。     

A novel method for preparing bimodal elastomeric networks

Summary Hydroxyl-terminated chains of poly(dimethylsiloxane) (PDMS) were end linked with a trifunctional silane containing 3-aminopropyl groups. CuCl₂ or CoCl₂ added to the networks forms complexes with the amino groups on the cross links, thus introducing additional chains that are very short. The resulting PDMS networks are in this sense bimodal, and were found to have increased values of the ultimate strength.     

A novel method for preparing poly(alkyl methacrylates) and poly(methacrylic acids) of varying tacticity

In order to synthesize poly(methacrylic acid) and poly(alkyl methacrylates) over a wide range of polymer tacticity, the anionic polymerization of the following alkyl methacrylates (ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-amyl, n-hexyl, n-octyl, n-decyl, n-lauryl, and n-octadecyl) in toluene using phenylmagnesium bromide initiation was studied. It was found that the amount of isotactic polymer structure generally decreased as the size of the ester group increased. In all cases, the polymers had greater than 50% isotactic triad structure. Whether the polymerization was carried out at 0° or ?78°C had little or no effect on the tacticity of the polymer produced. It was found that the poly(alkyl methacrylates) produced could be hydrolyzed in concentrated sulfuric acid to poly(methacrylic acid). The poly(methacrylic acid) produced in the hydrolysis could be esterified with diazomethane to give poly(methyl methacrylate) or with diazoethane to give poly(ethyl methacrylate) with the same tacticity as the poly(alkyl methacrylate) from which the poly(methacrylic acid) was derived. It is possible, therefore, to produce poly(alkyl methacrylates) of a desired tacticity by polymerizing the appropriate monomer, hydrolyzing, and reesterifying the resultant poly(methacrylic acid) with a diazoalkane to give the desired poly(alkyl methacrylate).     

花状Ni(OH)2的制备及其电化学性能研究

以NiCl₂·6H₂O和NH₃·H₂O为原料,采用简单的水热法,借助表面活性剂CTAB成功合成了β-Ni(OH)₂。研究表明,该材料具有以纳米片相互穿插构成的花状分层微米球结构,比表面积高达45 m²?g^-1。电化学测试表明材料具有良好的电化学性能,在3 A?g^-1的充放电电流密度下,Ni(OH)₂的比容量达到505 C?g^-1,在超级电容器领域具有良好的应用前景。     

球形覆Co氢氧化镍的合成及性能研究

在自行设计制作的管式反应器中,采用化学沉积包覆的方法在球形氢氧化镍表面包覆了一层Co(OH)2膜,通过实验发现,pH值和络合剂的浓度对包覆反应有很重要的影响.表面覆钴量不同,其表面形貌、电化学循环稳定性和大电流充放电性能也有很大差异.本文利用X射线衍射仪、扫描电镜和恒流充放电技术测试了其相结构、表面微观形貌和循环寿命等方法,确定了合适的氢氧化镍表面覆钴量.     

超级电容器复合电极材料Ni(OH)_2/GO的制备及其电化学性能研究

采用液相共沉淀法制备氢氧化镍/石墨烯(Ni(OH)2/GO)复合材料,通过电池测试系统检测对比Ni(OH)2与GO复合前后材料的电化学性能。测试结果表明,将Ni(OH)2与GO进行复合之后,复合材料的比电容达到141.3F·g-1,循环100次后容量保持率为94.6%,较单一的Ni(OH)2有较大的提高。     

Excellent performance MWCNTs-GONRs/Ni(OH)2 electrode for outstanding supercapacitors

Due to the unconventional properties of MWCNTs-GONRs (multiwalled carbon nanotubes-graphene oxide nanoribbons), we have tried to use it as a carbon resource for supercapacitors. MWCNTs-GONRs/Ni(OH)₂ electrode was obtained by hydrothermal method. Velvet α-Ni(OH)₂ was prepared above NF (nickel-foam) loaded with MWCNTs-GONRs. This layered design can effectively promote the diffusion of ions and increase the active site for MWCNTs-GONRs/Ni(OH)₂ electrode, thus enhancing the electrochemical performance. The electrode exhibits extraordinary electrochemical performances in electrochemical testing, such as supernal specific capacitance (1713.2 F g⁻¹) and prominent working time. In addition, supercapacitors was assembled with MWCNTs-GONRs/Ni(OH)₂ and active carbon as materials. Which represents a prominent energy density (41.23 Wh kg⁻¹), high power (6.80 kW kg⁻¹) and prominent cycling stability property (95.18%, 3000 times). The electrode prepared in this work provides a clue to enlighten people for energy storage.     

A simple and environmentally friendly method of preparing sulfide photocatalyst

This paper reports the preparation of (AgIn)_xZn_2(1−x)S₂ solid solutions from acidic aqueous solutions consisting of silver nitrate, indium nitrate, zinc nitrate, and thioacetamide, without using toxic H₂S gas. The reaction sequence of this multicomponent material was investigated, as well as the post thermal treatment conditions. The formation of quaternary semiconductor solid solutions after 800 °C annealing were determined by X-ray diffraction. The peaks in the XRD patterns shifted to higher angles with an increase of [Zn]/[In] in the precursor solutions. Band gaps of the (AgIn)_xZn_2(1−x)S₂ solid solutions were estimated to be 2.11-2.45 eV by diffuse reflection UV-Vis spectra. In addition, the band gap energy increased with [Zn]/[In] accordingly. The precipitates after heat treatment had a layered structure, as revealed by SEM; the compositions were analyzed by EDS. The photocatalytic H₂ evolution rates in sacrificial reagents under a 300 W Xe lamp of Pt-loaded (AgIn)_xZn_2(1−x)S₂ solid solutions were measured. A H₂ evolution of 340 μmol/h for 0.5 g photocatalyst was obtained. The particles retained the photocatalytic activity for at least 100 h. This study demonstrates that AgInS₂-ZnS solid solution particles can be prepared from a completely aqueous route.     

非晶态Ni(OH)2电极材料的制备工艺

采用微乳液快速冷冻沉淀法制备非晶态Ni(OH)2. 通过单因素及正交实验研究反应体系的pH值、反应温度和时间等因素对制备的非晶态Ni(OH)2电化学性能的影响. 结果表明,主要影响因素为pH值,其次为反应温度和时间. 采用TX-100/正丁醇/环己烷/水体系,控制TX-100与正丁醇的体积比为1:15,W值(水与表面活性剂质量比)为15.1,pH为12,反应时间2 h,反应温度55℃的条件下进行反应,放入0~5℃的超低温恒温槽中快速冷冻沉淀,合成出Ni(OH)2非晶相粉体电极活性材料,该材料的放电比容量达333.22 mA×h/g,具有较高的电化学容量. 初步探讨了微乳液快速冷冻沉淀法制备非晶态Ni(OH)2粉体的作用机理.     

Ni（OH）_2纳米材料的制备研究

综述了Ni（OH）2纳米材料的主要合成方法,介绍了各种制备方法的工艺条件及主要特点,指出氢氧化镍作为电池正极材料具有光明的前景,但对生产技术还需进一步研究。     

Ni(OH)2催化剂催化氧化醇的研究

采用共沉淀法制备了Ni(OH)2催化剂,该催化剂对温和条件下以分子氧为氧化剂的苯甲醇及烯丙醇类的氧化反应有十分理想的催化效果,并且完全可以通过简单的处理回收利用.     

一种简便测定环境样品中Cr(Ⅲ)的新方法

根据Luminol H2O2 Cr(Ⅲ)体系在碱性条件下产生很强的化学发光的原理,用光电二极管作检测器测定环境样品中的Cr(Ⅲ)。本方法具有分析速度快、选择性好、检测装置结构非常简单,成本低等优点。其检测限为5.0×10-8g/mL,线性范围为5.0×10-8～5.0×10-4g/mL,相对标准偏差小于5.0%。在实际样品的分析中,取得了令人满意的结果。     

Ni(OH)_2/C作为锂离子电池负极材料的研究

采用控制沉淀法制备Ni(OH)2/C复合材料,用XRD和SEM表征材料的结构和形貌。首次将材料用于锂离子电池,通过充放电测试、循环伏安法和交流阻抗实验研究其嵌/脱锂行为和电化学性能。结果表明,Ni(OH)2/C复合材料具有嵌/脱锂性能,首次可逆比容量达到992mAh/g,20次循环后的可逆比容量为211mAh/g,循环效率为95.6%,高于Ni(OH)2材料(128mAh/g和94.4%),循环性能的改善可归因于掺杂石墨后,使电极电导率明显提高,同时减缓体积效应。