Ni(OH)_2水浆蒽醌催化水热还原制备超细镍粉

以蒽醌作催化剂，水热加氢还原从Ni（OH）2水浆制备了超细镍粉．研究了催化剂量、温度、时间、氢分压、浓度和pH等因素对还原速度和粉末粒度的影响，还原率通过X-射线衍射分析本被还原的镍来确定．用扫描电镜观察分析了粉末的粒度与形貌.研究表明，在温度高于200℃的条件下，蒽醌对Ni（OH）2浆料还原成金属镍粉是一种良好的催化剂．所得的粉末是平均粒径约为300nm的球状超细镍粉.     

液相还原法制备超细球形镍粉的工艺研究

以水合肼作为还原剂,在碱性条件下,不使用任何分散剂制备超细镍粉。使用引发剂,控制反应温度80℃,反应物Ni^2＋浓度可高达1．5mol／L。采用X射线衍射分析、扫描电镜等手段对样品进行了表征,结果表明：制得的镍粉纯度高,球形度好且表面光滑,分散性好,平均粒径约为150nm。     

原位化学沉积法制备镍包覆碳化硅颗粒复合粉体

以六水合氯化镍为镍源,水合肼为还原剂,在SiC的表面,采用原位化学沉淀法制得包裹均匀的Ni/SiC复合粉体.采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、傅立叶红外光谱仪(FT-IR)等测试表征手段研究了工艺条件对原位沉积反应的影响.研究发现不同络合反应时间形成的镍肼络合物前驱体和镀镍反应温度可以影响反应速率,从而控制Ni颗粒的沉积速率和包裹效果.对比结果表明:络合反应时间为5 min形成的镍肼络合物前驱体在50℃水浴温度下和络合反应时间为2h得到的镍肼络合物前驱体在60℃水浴温度下得到的复合粉体包裹效果最佳.     

Ni/γ-Al_2O_3催化乙基咔唑加氢性能研究

以自制的镍基催化剂对乙基咔唑进行加氢性能研究。实验采用γ-Al2O3为载体,在乙二醇溶液中以水合肼为还原剂,制备了不同负载量的Ni/γ-Al2O3催化剂,采用X射线荧光分析、X射线衍射等检测手段对其表征,并在0.1 L的高压反应釜中对乙基咔唑进行催化加氢。实验表明:当Ni负载量为20%时,Ni/γ-Al2O3催化剂具有较优的催化性能;在反应温度200℃、反应压力6 MPa、负载量为20%的Ni/γ-Al2O3用量1.5 g的加氢条件下,10 g乙基咔唑可以加氢0.280 mol,吸氢转化率达91.2%。     

表面活性剂对氢氧化镍制备的影响

近年来,在Ni(OH)2的制备中使用表面活性剂主要是制备纳米Ni(OH)2或超微粉末[1-4]。但由于纳米级或超微粉末Ni(OH)2不适合于目前以泡沫镍为基体的Ni-MH电池的生产,所以本实验制备Ni(OH)2晶体时,加入适量表面活性剂对颗粒表面进行改性,控制颗粒的生长和团聚,制备微米级Ni(OH)2。1实验部分以氨作配合剂利用化学沉淀法将硫酸镍溶液、氢氧化钠溶液、表面活性剂溶液、氨水以一定的比例并流加入反应器,连续搅拌,控制反应温度在50~60℃,pH值10~12之间。反应14~16 h后停止加料,陈化约8 h后,固液分离,洗涤沉淀,烘干得到氢氧化镍产品。在制备过…     

纳米镍粉上硝基苯加氢制苯胺反应性能研究

以NiSO4.6H2O、NaOH和H2为原料,采用低温固相法制备了分布均匀、平均粒径为20～35 nm的纳米镍粉,并采用X射线衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)和X射线光电子能谱分析(XPS)等微观分析手段对产物表面结构和价态进行了表征。研究了纳米镍粉加氢还原硝基苯制备苯胺体系中温度、氢压力、催化剂用量等因素对转化率的影响,并与Raney Ni的活性做了比较。结果表明,纳米镍粉催化加氢活性高于RaneyNi,是同条件下Raney Ni的9倍左右;催化剂用量4wt%～6wt%(质量含量,下同),温度为120℃为还原的最佳条件;同时发现氢压力对转化率也有着较大影响,当压力达到0.8 MPa,硝基苯转化为苯胺的转化率高达76.42%。     

非铁磁性超细镍粉的制备研究

研究了在碱性条件下,使用特殊的络合剂、分散剂TX-10,以及冰水浴室工艺条件,以水合肼作为还原剂制备非磁性镍粉的方法,其中反应物Ni2＋浓度为lmol／L,控制反应温度95℃,并使用引发剂。采用XRD、SEM等手段对样品进行了表征,结果表明：制得的镍粉纯度高,磁饱和强度低,球形度好且表面光滑,分散性好,平均粒径约为350nm。在水溶液中制备非铁磁性高分散性球形超细镍粉的方法,在国内外尚未见相关报道。     

2-(2''''-羟基-5''''-甲基苯基)苯并三唑-N-氧化物的合成

以水合肼为还原剂,用偶合物合成了2-(2'-羟基-5'-甲基苯基)苯并三唑-N-氧化物.考察了原料比,氢氧化钠用量及浓度等因素对产品收率的影响.得到了适宜的反应条件偶合物、水合肼与氢氧化钠的摩尔比为10.535.3,氢氧化钠溶液的浓度为18%,反应温度80～82℃,收率达95%以上,纯度为99%.     

溶剂热法制备铜与氧化亚铜纳米晶

利用溶剂热法，以五水硫酸铜、氢氧化钠、无水乙醇为原料，在无水条件下通过乙醇还原氧化铜制得了形状均一、分散性较好的纳米铜颗粒；在有水条件下通过乙醇还原氧化铜合成出了一维氧化亚铜纳米棒。利用X射线粉末衍射仪（XRD）及高分辨透射电镜（HRTEM）对合成产物进行了物相与形貌分析。在实验中还发现反应温度与溶剂中水的加入量是影响乙醇还原性的主要因素，并由此决定了最终产物的相组成。     

一种微反应制备纳米镍粉的研究

以微反应器为核心反应设备,以硫酸镍为主要原料,水合肼和硼氢化钠为混合还原剂,非离子表面活性剂PVPK-30为分散剂,反应体系p H为11的条件下,控制反应温度为80℃,反应物Ni2+浓度为0.75mol/L,发生超声强化微反应,并辅以带搅拌的超声清洗装置清洗,磁力吸附装置收集,真空干燥箱干燥等过程,可制备得粒径为100nm左右、形貌为球形、尺寸分布窄的纳米镍粉。通过对新型微反应器、混合还原剂、镍离子初始浓度、反应温度等的研究,研究采用此种超声强化微反应法对制备纳米镍粉的粒径及形貌的影响。     

Controllable preparation of Ni nanoparticles for catalysis of coiled carbon fibers growth

The mass preparation of high-purity coiled carbon fibers (CCFs) remains challenging due to the high complexity and low controllability of reaction. In this work, a controllable growth of Ni particles was fulfilled by liquid phase reduction of nickel sulfate with hydrazine hydrate. The impacts of the reaction temperature, NaOH concentration, and reaction time on the particle size and purity were investigated. The as-deposited Ni particles were characterized by scanning electron microscopy and X-ray diffraction. In addition, these Ni particles were also applied in preparing high-purity CCFs both on graphite and ceramic substrates. The diameter of the as-grown carbon microcoil was about 500 nm, and the related growth mechanism was discussed.     

Effect of synthesis conditions on preparation of nickel metal nanopowders via hydrothermal reduction technique

Synthesis of nickel nanopowders from aqueous solution using hydrothermal reduction method with hydrazine hydrate as a reducing agent and Cetyl trimethyl ammonium bromide (CTAB) as a surfactant was investigated. Statistical design was used to study the effects of reaction time, concentration of nickel chloride, and concentration of surfactant on the nickel particles size. Formed nickel particles were characterized using XRD and SEM. The formation of nickel single phase was revealed from XRD patterns. On the other hand, SEM showed that the nickel particles are in nanosized ranges from 55 nm to 250 nm. The analysis of the results indicated that the reaction time and surfactant addition were the controlling factors. The reduction of nanocrystalline nickel hydroxide Ni(OH)₂ into Ni is the possible formation mechanism.     

球形镍氧化物制备硫酸镍的方法研究

以球形镍氧化物为原料,研究了制备高纯硫酸镍的方法。首先借助X射线衍射仪（XRD）和X射线光电子能谱仪（XPS）对球形镍氧化物的主要成分进行表征,确认其主要成分为氧化镍;其次对球形镍氧化物浸取制备较高纯度的硫酸镍条件进行了优化,确立了硫酸浓度为1.84 mol/L、反应温度为200 ℃、固液比为0.3 g/mL、反应时间为6 h为最优反应条件;最后利用高温条件下（250 ℃）获得的一水合硫酸镍固体,提出了将其再次溶解生产pH和镍浓度可控的高纯硫酸镍溶液的方法。     

Precipitation and Calcination Processes for Yttrium Aluminum Garnet Precursors Synthesized by the Urea Method

Yttrium aluminum garnet (YAG) precursors for transparent ceramics were synthesized by the urea method under various [urea]/[metal ions] ([U]/[M]) conditions. Monophase YAG was obtained from solutions with a high [U]/[M] ratio after calcination at a temperature of 1200°C. The condition of the precipitates seemed to indicate that the yttrium compounds had precipitated onto the aluminum compounds. The surface morphology and size of the particles were controlled by the [U]/[M] ratio. The different reaction sequences of YAG crystallization for low- and high-ratio samples were dependent on morphology, size, and the quantity of chemical species that was precipitated as carbonate and/or sulfate compounds.     

Fabrication and characterization of NiO nanoparticles by precipitation from aqueous solution

Present work involves synthesis of NiO nanoparticles using chemical homogeneous precipitation (CHP) method as a facile procedure. Ammonia as a complex agent was used in this method. Effects of different types of complexation-precipitation methods on the crystallinity and morphology of nanoparticles were investigated. NiO particles were prepared by direct precipitation method from NiSO₄ solution to compare crystallinity and morphology of NiO particles with particles obtained via complexation-precipitation methods. Our major intent was to investigate the effect of complex agent on the crystallization and growth of NiO nanoparticles. Results showed that the best condition for synthesizing spherical NiO shape was using NaOH as decomposing agent, of which the consequence was more uniformity and spherical nanoparticles with a diameter in the range of 40–60 nm. The size of the nickel oxide and nickel hydroxide nanoparticles was estimated by X-ray powder diffraction (XRD) pattern. The chemical structure information of the particles was studied by Fourier transform infrared (FT-IR) spectroscopy. Spherical, elliptical, sheet or flowerlike shapes were detected by field emission scanning electron microscopy (FESEM) analysis. Results showed that by the use of ammonia as complex agent, crystalline state and particles size distribution of NiO nanoparticles improved.     

Synthesis and characterization of ZnO:Ni thin films grown by spray-deposition

In the present study, nickel-doped zinc oxide thin films (ZnO:Ni) at different percentages (0–10%) were deposited on glass substrates by using a chemical spray technique. The effect of Ni concentration on the structural and optical properties of the ZnO:Ni thin films was investigated. The effect of Ni contents on the crystalline structure and optical properties of the films was systematically investigated by X-ray diffraction (XRD), scanning electronic microscopy (SEM), UV–vis, Photoluminescence spectra PL, and Raman spectrometry. The XRD analysis showed that both the undoped and Ni-doped ZnO films were crystallized in the hexagonal structure with a preferred orientation of the crystallites along the [002] direction perpendicular to the substrate. The XRD analysis also showed that the films were well crystallized in würtzite phase with the crystallites preferentially oriented towards (002) direction parallel to the c-axis. SEM study reveals the surface of NiZnO to be made of nanocrystalline particles. The SEM images showed a relatively dense surface structure composed of crystallites in the spherical form whose average size decreases when the [Ni]/[Zn] ratio increases. The optical study showed that all the films were highly transparent. The band gap decreased up to the 7 at% Ni doping level, but the band gap increased after 10 at% Ni doping level. All thin films exhibited approximately 80% and above transmittance in the visible region. PL spectra of undoped and Ni-doped ZnO thin films showed some marked peaks at 376, 389, 494, and 515 nm. The obtained results revealed that the structures and optical properties of the films were greatly affected by doping levels. These films are useful as conducting layers in electro chromic and photovoltaic devices. Finally, all results were discussed in terms of the nickel doping concentration.     

化学法制备电极用超细铜粉

以CuSO4溶液为原料,采用NaOH沉淀-葡萄糖预还原-水合肼还原工艺（简称两步液相还原法）制得了粒度均匀可控、分散性好、适用于陶瓷电容器电极的球形超细铜粉。实验研究了葡萄糖预还原、水合肼的添加方式以及添加剂聚乙烯吡咯烷酮（PVP）和NH4Cl对超细铜粉粒度和形貌的影响。结果表明,葡萄糖预还原和水合肼的分步添加均有利于超细铜粒子的均匀生长,适量PVP的加入有助于超细铜粉粒径均匀并使其形貌趋于一致,NH4Cl可使铜粉的粒径变小,当Cu与NH4Cl的摩尔比为1∶1时铜粉的形貌会由类球形向正多面体转变。     

NaOH亚熔盐法分解钾长石矿

以高浓度NaOH溶液为亚熔盐介质分解钾长石矿精粉,考察了矿物粒径、NaOH溶液浓度、搅拌速度、反应时间、反应温度、液固比对K+溶出率的影响,并对分解过程动力学进行分析. 结果表明,100 mm粒径钾长石矿精粉的最佳反应条件为：NaOH初始浓度60%(w)、反应温度约160℃、搅拌速度400 r/min、液固质量比4:1、反应140 min,该条件下K+溶出率大于98%. 钾长石的分解符合粒径恒定的缩核模型,反应初期固相产物层内扩散为速控步骤. 80~140℃下,反应的表观活化能为110.42 kJ/mol.