球形微米镍颗粒的液相体系制备及应用

本研究采用液相还原法,选用六水合硫酸镍为镍源,水合肼为还原剂,在封端剂聚乙烯吡咯烷酮的辅助下,制备得到球形微米镍颗粒。所制备的球形微米镍颗粒粒径约为3 μm,粒径分布均匀,表面粗糙度较低。为了获得球形微米镍颗粒的最优工艺方案,分别探究了PVP浓度、氢氧化钠和水合肼用量及反应温度等工艺参数对产物形貌的影响。研究发现,PVP能够有效控制镍原子的排布和沉积,NaOH可调节反应的pH值,确保水合肼持续还原Ni₂₊^,温度会影响体系的还原反应速率。结果表明：当反应体系使用的PVP浓度为0.5 M、NaOH用量为2.5 mL、水合肼用量为5 mL时,在 60 ℃下水浴反应可获得表面粗糙度低的球形微米镍颗粒,其电导率为5×10₅ S.m_-1^,饱和磁化强度为49.34 emu.g_-1^{。通过添加去离子水、异丙醇和羧甲基纤维素的混合溶液},将球形微米镍颗粒配制成25 wt%的导电油墨,并在纸基表面绘制导电线路,经测试该线路的电导率为1.28×10₃ ^S.m_-1^,此电路在弯折条件下,呈现出良好的工作稳定性。     

水基溶胶-凝胶法制备稀土/碱土金属硅酸盐纳米粉

采用水基溶胶凝胶法,以廉价的无机盐Y2O3,MgO为前驱物,Si(OC2H5)4为络合剂,PEG4000为复合表面活性剂,氨水调节pH值,并利用无水乙醇超声分散技术,成功制备了分散性良好的稀土碱土金属复合硅酸盐纳米粉xY2O3·yMgO·zSiO2(YMS),考察了初始溶液的pH值、温度及浓度对溶液—溶胶—凝胶转变的影响,并利用TG DTA,XRD,TEM分析手段对复合硅酸盐纳米粉YMS的性质进行了研究。实验表明,在60℃相似文献   

复合材料K_8[Fe(H_2O)CdW_(11)O_(39)]/PANI/ZrO_2的制备、表征及光催化性能

采用静电自组装法制备了复合材料K_8[Fe(H_2O)CdW_(11)O_(39)]/PANI/ZrO_2.运用UV,IR,XRD,SEM-EDS和N_2吸附-脱附的检测手段对其进行了表征,并以该化合物作为催化剂,研究了其对孔雀石绿溶液的光降解情况.通过实验确定最佳的光降解条件:孔雀石绿溶液的初始浓度为25mg/L,孔雀石绿溶液的初始pH值为2,K_8[Fe(H_2O)CdW_(11)O_(39)]/PANI/ZrO_2的用量为0.05g.在最佳的条件下,孔雀石绿溶液的脱色率可达98.68%.因此,K_8[Fe(H_2O)CdW_(11)O_(39)]/PANI/ZrO_2是一种光催化性能良好的复合材料.     

K_8[Cu(H_2O)ZnW_(11)O_(39)]/PANI/ZrO_2复合材料的制备与光催化性能研究

采用静电自组装法制备了复合材料K_8[Cu(H_2O)ZnW_(11)O_(39)]/PANI/ZrO_2,并采用IR、UV、XRD、N_2吸附-脱附、SEM、XPS、TG的检测手段对其进行了表征,且以制备的K_8[Cu(H_2O)ZnW_(11)O_(39)]/PANI/ZrO_2为催化剂,考察了K_8[Cu(H_2O)ZnW_(11)O_(39)]/PANI/ZrO_2的光催化活性,以二甲酚橙为模型,在紫外光照射条件下,确定最佳光催化条件为:二甲酚橙溶液的初始浓度为5 mg·L~(-1),二甲酚橙溶液的初始pH值为4,K_8[Cu(H_2O)ZnW_(11)O_(39)]/PANI/ZrO_2的用量为0.0200 g。最佳条件下,二甲酚橙溶液的脱色率可达93.72%。     

聚乙烯醇高聚物保护疏水性氢氧化铁的机理——多核氢氧化铁-聚乙烯醇包合物的形成

实验部分1.试剂和仪器:FeCl_3·6H_2O AR;NaOH AR;PVA(聚乙烯醇)牌号PVA-124日本进口分装.UV分光光度计(日本UV-300);波长488nm激光束(COHERENT,innoVA 70);X射线光电子能谱(XPS)仪(沈阳Np-1型);红外光谱(IR)仪(美国PE-577);电子自旋共振(ESR)仪(西德ER-420). 2.试样制备:A:5%PVA水溶液;B:100ml pH=2的A含0.1克FeCl_3·6H_2O;C,D:100ml pH=7和13的A分别加入0.1克FeCl_3·6H_2O形成的红棕色透明溶液;E:试样D的     

Al2O3负载Pt催化剂的合成及其甲醇低温催化燃烧性能研究

采用一步合成法制备了Al₂O₃负载Pt催化剂Pt/Al₂O₃,以甲醇催化燃烧作为目标反应研究了其催化性能,考察了还原剂浓度、表面活性剂用量、表面活性剂浓度和煅烧温度对Pt/Al₂O₃甲醇低温催化燃烧性能的影响。结果表明,当还原剂浓度为0.1 mol/L、表面活性剂(CTAB)用量为8.53 g/g_cat.、表面活性剂浓度为0.1 mol/L、煅烧温度为600℃时,所得催化剂的活性最高,25℃下甲醇催化燃烧的转化率达到52%。而改进一步合成法制备的负载型催化剂Pt/Al₂O₃具有更高的甲醇催化燃烧活性,25℃下甲醇催化燃烧的转化率为84%。     

高反应浓度下制备不同形貌氧化亚铜的简易方法

在常压,70 ℃,高反应浓度和不加任何添加剂的条件下,硫酸铜经与NaOH反应后用葡萄糖还原获得了球形、立方体、多面体、星形和正八面体形貌的Cu₂O粒子。用X射线粉末衍射,扫描电镜和激光粒度仪对所制备的产品进行了表征。改变反应原料的加料方式和NaOH的浓度可获得不同形貌的Cu₂O粒子。在恒温下先加NaOH溶液再加浓度为0.1 g·mL^-1的葡萄糖溶液的分步加料方式下,当NaOH的浓度依次为0.15、0.225、0.3和0.45 g·mL^-1时分别得到立方体、多面体、星形、和正八面体;在室温下,NaOH 和葡萄糖分步加料后程序升温,得到球形;恒温,氢氧化钠和葡萄糖同时加料方式下产物主要为球形。     

铜胶体的制备及光谱研究

以水合肼为还原剂通过控制化学还原反应，从硫酸铜溶液中制备出纯金属铜胶体，研究了表面活性剂的浓度对胶体粒子大小及团聚等的影响，紫外－可见光谱与胶体粒子尺寸及团聚的关系，结果表明，在较高浓度的表面活性剂存在下，能有效地防止粒子的团聚，有利于球形小粒子的生成。     

SDS-PVP水溶液中超细镍粉的制备

在十二烷基硫酸钠(SDS)-聚乙烯吡咯烷酮(PVP)混合水溶液中, 采用水合肼还原氯化镍制备超细镍粉. SEM结果表明, 该超细镍粉为球形, 表面呈现针状叠合的特殊形貌. XRD结果表明,该超细镍粉由平均粒径约为10 nm的面心立方结构(fcc)的原生纳米镍晶粒组成, 且主要沿(111)晶面生长. TEM清晰观察到原生纳米镍晶粒在PVP的空间桥联作用下自组装成超细镍粉的中间过程. SDS-PVP的组成对超细镍粉的粒径和表面形貌有显著影响, 在一定浓度范围内, 随着SDS或PVP浓度增大, 原生纳米镍晶粒和超细镍粉的平均粒径均呈减小趋势, 表明通过改变SDS-PVP组成可以调控超细镍粉的粒径和形貌.     

2-羟基-4-磺酰氨基苯-3-(4-硝基苯)-三氮烯的合成及与镍的显色反应

合成了新的三氮烯试剂2 羟基4 磺酰氨基苯3 (4 硝基苯) 三氮烯(HSNPT) ,并研究了在TritonX 1 0 0表面活性剂存在下与镍的显色反应。在pH 1 0～1 2. 0的Na2 B4 O7 NaOH缓冲溶液中,试剂与镍形成配合比为3∶1型淡黄色配合物。配合物最大负吸收峰位于λ=5 40nm处,表观摩尔吸光系数1 .1 8×1 0 5L·mol- 1·cm- 1。Ni2 +的质量浓度在0～480 μg/L范围内符合比尔定律。用拟定方法测定合金钢样品中的微量镍,结果满意。     

镍负载量对乙醇水蒸气重整制氢催化性能和催化剂的影响

采用稳态实验对镍负载量对Ni/MgO催化剂在乙醇水蒸气重整反应的影响进行了研究。结果表明，在101.3kPa下，镍负载量越高，催化剂的活性越高。对于催化剂的选择性，存在一个最佳镍负载量为10%Ni/MgO。按选择性从大到小排序，不同镍负载量的催化剂为：10Ni/MgO>15Ni/MgO>12.5Ni/MgO>7.5Ni/MgO≈5Ni/MgO。热分析表明，焙烧过程中不同镍负载量的催化剂镍前体与载体前体之间发生的相互作用不同。XRD和TPR 表征结果显示，催化剂的晶体结构和还原特性也与催化剂上镍的负载量有关。焙烧过程中样品10Ni/MgO上镍前体与载体前体发生了两种相互作用, 并且其氧化态与其他催化剂相比具有特殊的结构和还原性。说明催化剂的选择性不仅受活性相Ni的影响而且受Ni活性相周围环境的影响。     

Determination of ultra-trace amounts of nickel in environmental samples by atomic absorption spectrometry with in-situ trapping of volatile species in an iridium–palladium coated graphite furnace

A sensitive and accurate method is described for the determination of ultra-trace nickel in environmental samples with in-situ trapping of volatile species in iridium-palladium coated graphite furnace atomic absorption spectrometry. The effects of the conditions for the generation and collection of volatile nickel species, such as medium acidity, potassium borohydride concentration, enhancement reagent concentration, reaction temperature, as well as graphite tube coating, carrier gas flow rate and trapping time were investigated. Phenanthroline was selected as the enhancement reagent due to its good enhancing effect, and iridium–palladium coating was used for the in-situ trapping of volatile nickel species at 300°C. Under the optimal conditions, the calibration curve was linear from 0.21 up to 30.0 ng mL^?1 with correlation coefficient of 0.9991, the detection limit (S/N = 3) was 0.21 ng mL^?1 for 4 mL sample volumes and the relative standard deviation for 11 determinations of Ni at 10 ng mL^?1 was 3.5%. The results found by the proposed methods are accordant with the certified values of water, soil and tea certified reference materials. The proposed methods have been applied for the determination of ultra-trace Ni in tap, river and wastewater, as well as rice and soil samples, with recoveries ranging from 97.3 to 100.5%.     

混合配体镍配合物[Ni（NCS）2（phen）2]的合成、晶体结构及荧光性质

合成了含异硫氰酸根和邻菲咯啉（phen）混合配体的镍配合物[Ni（NCS）2（phen）2],通过红外光谱、紫外光谱和X射线单晶衍射等手段对其结构进行了表征.研究了配合物的固体荧光光谱.单晶结构解析结果表明,标题化合物属于正交晶系,Pbcn空间群,晶胞参数为：a=1.296 2（2）nm,b=1.019 0（1）nm,c=1.759 5（2）nm,V=2.323 9（4）nm3,Z=4,Dc=1.530 g/cm3,μ=1.043 mm-1,F（000）=1 096,R1=0.042 1,wR2=0.108 1.配合物中镍离子采用6配位的八面体配位构型,晶体堆积中通过π-π作用形成一维超分子结构.     

镍钴氢氧化物的制备及其电化学性能

采用化学共沉淀法成功制备了片状镍钴氢氧化物,并探究了不同镍钴物质的量比对样品形貌及电化学性能的影响。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱仪(XPS)及比表面积孔径分析仪(BET)对样品的结构、形貌进行了表征,并利用循环伏安法、恒电流充放电法等对其电化学性能进行了分析。结果表明,n(Ni)∶n(Co)=4∶1的样品直接用作电极材料时,具有最好的电化学性能:在0.5 A/g的电流密度下拥有1852 F/g的高比容量;电流密度增大20倍时,仍拥有1330 F/g的高比容量。以镍钴氢氧化物为正极,活性炭为负极组装的非对称式超级电容器在346 W/kg的功率密度下,能量密度达52 Wh/kg,在循环10000圈之后电容保持率为92%。优异的电化学性能表明,片状镍钴氢氧化物是很有应用潜力的电极材料之一。     

1-偶氮苯-3-(3-硝基-5-氯-2-吡啶)三氮烯的合成及其与镍(Ⅱ)离子的显色反应

合成了新显色剂1-偶氮苯-3-(3-硝基-5-氯-2-吡啶)三氮烯(ABNCPDT),并研究了它与镍的显色反应.在pH 10.5的Na2B4O7-NaOH缓冲溶液中,TX-100表面活性剂存在下,试剂与镍生成4∶1型红色配合物.配合物的最大吸收峰位于540 nm,表观摩尔吸光系数为1.86×105L.mol-1.cm-1.N i2+浓度在0~480μg/L范围内符合比尔定律.用拟定方法测定铝合金中微量镍,结果满意.     

Synthesis and Crystal Structure of Bis(S-methyl-β-N- (4-dimethylaminophenyl)methlenedithiocarbazate) Nickel (Ⅱ)

11NTRoDUCT1ONRecently,transitionmetalorganometallicandcoordinationcomplexeshavee-mergedaspotentialbuildingblocksfornonlinearoptical(NLO)materials(l-5i.Com-paredwlthorganlcmolecu1es,metalcomplexesofferalargervarietyofstructures,comparabIeor,insomecases,higherenvironmenta1stabilityandamuchgreaterdi-versityoftunableelectronicpropertiesbythevirtueofthecoordinatedmetalcen-tert6i.Thethio-Schiffbaseligandderivedfromdithiocarbazatesandthiosemicar-bazidescancoordinatereadilywithtransitionmetalstog…     

新型钛基镍电极对肼氧化反应的电催化活性

A novel titanium-supported nickel electrode(Ni/Ti) was fabricated by a hydrothermal process using NiSO4 and hydrazine as raw materials. The structure of Ni/Ti was characterized by SEM and EDS. Oxidation of hydrazine on the Ni/Ti electrode in 1 mol·L-1 NaOH solution was studied with cyclic voltammograms(CV) and chronoamperometry (CA).The results show that Ni/Ti electrode was electrochemically active towards hydrazine oxidation. The high current density was recorded on the Ni/Ti electrode,and the onset potential for the hydrazine oxidation was-0.3 V as the hydrazine concentration was 70 mmol·L-1. This novel nickel electrode would be a promising anodic material used in direct hydrazine fuel cells.     

Ball-milling processing of nanocrystalline nickel hydroxide and its effects in pasted nickel electrodes for rechargeable nickel batteries

Nanocrystalline Ni(OH)₂ powder synthesized by a chemical precipitation method was processed using the planetary ball milling (PBM), and the physical properties of both the ball-milled and unmilled Ni(OH)₂ were characterized by scanning electron microscopy (SEM), specific surface area, particle size distribution, and X-ray diffraction. It was found that the PBM processing could significantly break up the agglomeration, uniformize the particle size distribution, increase the surface area, decrease the crystallite size, and reduce the crystallinity of nanocrystalline β-Ni(OH)₂, which were advantageous to the improvement of the electrochemical activity of Ni(OH)₂. The ball-milled nanocrystalline (BMN) Ni(OH)₂ was then used to alter the microstructure of pasted nickel electrodes and improve the distribution of the active material in the porous electrode substrate. Electrochemical performances of pasted nickel electrodes with a mixture of BMN and spherical Ni(OH)₂ as the active material were investigated, and were compared with those of pure spherical Ni(OH)₂ electrodes. Charge/discharge tests showed that BMN Ni(OH)₂ addition could enhance the charging efficiency, specific discharge capacity, discharge voltage, and high-rate capability of pasted nickel electrodes. This performance improvement could be attributed to a more compact electrode microstructure, better reaction reversibility, and lower electrochemical impedance, as indicated by SEM, cyclic voltammetry, and electrochemical impedance spectroscopy. Thus, it was an effective method to modify the microstructure and improve the electrochemical properties of pasted nickel electrodes by adding an appropriate amount of BMN Ni(OH)₂ to spherical Ni(OH)₂ as the active material.     

Thermal Treatment of Sol-Gel Derived Nickel Oxide Xerogels

Very fine nickel hydroxide and oxide xerogel powders were prepared using a new sol-gel synthesis procedure in which nickel ethoxide was produced through the reaction of nickel chloride, as a precursor, with sodium ethoxide in dehydrated ethanol, followed by the hydrolysis of nickel ethoxide with ammonia and drying the resulting hydrogel under subcritical pressures to form the xerogel. The effects of thermal treatment on the surface area, pore volume, crystallinity and particle structure of the resulting xerogels were investigated and found to have significant effects on all of these properties. Overall, the xerogel remained amorphous as Ni(OH)₂ space up to 200°C, with little change in the surface area and pore volume. At 250°C, the Ni(OH)₂ began to decompose and form crystalline NiO with the uniformity of the crystals increasing with an increase in temperature. The surface area and pore volume decreased sharply when increasingthe temperature beyond 250°C; this was the temperature where maximums of about 270 m²/g and 0.33 cm³/g were exhibited by this composite amorphous Ni(OH)₂ and crystalline NiO xerogel powders. At the higher calcination temperatures, very uniform NiO crystals with average crystallite sizes of 1.7 nm and 14.5 nm were obtained at 400 and 600°C, respectively.     

Magnetic property and structural study of nickel supported on reduced graphene oxide prepared by chemical vapor deposition

Nickel supported on reduced graphene oxide was synthesized by chemical vapor deposition technique. The crystal structure and magnetic properties of the prepared sample were studied by means of Raman spectrometry, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), inductively coupled plasma optical emission spectrometry (ICP-OES), and vibrating sample magnetometry (VSM). The result of Raman spectroscopy revealed the structure of few-layer graphene as the support for Ni nanoparticles. XP spectrum confirmed the presence of metallic Ni on the a few-layer graphene surface. TE micrograph showed that the nickel nanoparticles were sphere shaped and the mean particle size is about 20 nm deposited on the reduced graphene oxide. The magnetic study showed the ferromagnetic behavior of 3.2 wt% nickel over reduced graphene oxide at room temperature.