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丙三醇-变频微波-水热法制备氢氧化镁晶须 总被引:5,自引:0,他引:5
以MgCl2·6H2O和NaOH为原料, 采用丙三醇-变频微波-水热法制备了优质氢氧化镁晶须. 采用XRD, SEM和TEM进行了物相、粒度、晶体形貌和结构分析. 考察了丙三醇-变频微波-水热法工艺对氢氧化镁晶须晶形、结构及分散性的影响. 实验发现, 在水热反应体系中加入体积分数为15%的丙三醇, 用变频微波加热, 在180 ℃反应6 h, 可获得粒度分布均匀、晶形和分散性好、表面光滑及缺陷少的优质氢氧化镁晶须. 在透射电镜下估算晶须直径约为0.1~0.3 μm, 长度约为80~110 um. 初步分析了变频微波和丙三醇对氢氧化镁晶须生长的作用. 相似文献
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以三聚磷酸钠为表面活性剂,采用水热合成法制备了氧化锌纳米片。采用场发射扫描电镜,透射电镜,紫外可见分光光度计和荧光光谱仪对氧化锌纳米片的显微结构和光学性能进行了表征,并对氧化锌纳米片的形成机理进行了探讨。结果表明:在220 ℃水热反应28 h可得到尺寸大约为600 nm × 500 nm × 50 nm(长×宽×高)结晶良好的六角形氧化锌纳米片,氧化锌纳米片对可见光的反射率超过90%,对紫外光的反射率小于20%,在395 nm附近均存在较强的紫外发射峰。氧化锌纳米片的形成是由于氧化锌晶体的正极面{001}晶面上显露的OH-悬健部分被具有负电性的磷酸根取代,这种取代的发生,阻碍了溶液中的生长基元Zn(OH)42-在该晶面上叠合,使得本应生长最快的(001)晶面生长受限,所以得到了片状的纳米氧化锌。 相似文献
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采用微波水热法,以醋酸镉(Cd(CH3COO)2.2H2O)为镉源,硫脲(CS(NH2)2)为硫源,制备出了具有单分散球形形貌的CdS纳米晶。应用X射线衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)、能量色散谱仪(EDS)、高分辨透射电子显微镜(HR-TEM)、紫外可见吸收光谱(UV-Vis)等测试手段对样品的物相、形貌、元素组分及吸光性能进行了表征,并以罗丹明B溶液的降解脱色反应来考察了其的光催化活性。结果表明:随着S/Cd物质的量比(nS/nCd)逐渐增大,产物会出现由刺球链状向分散球形过渡的规律性变化。在一定的nS/nCd比的条件下可以合成出大小均匀、分散性较好的六方相CdS纳米球。样品对可见光有较强吸收,存在着一定的红移现象。在可见光照射下,硫化镉单分散纳米球具有更高的光催化活性。 相似文献
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以氯化镁和氢氧化铵为原料,采用气体扩散技术制备了垂直排列氢氧化镁纳米薄片。利用场发射扫描电子显微镜(FE-SEM)、X射线衍射(XRD)、红外光谱(IR)以及差热分析(DTA)等分析测试技术研究了纳米氢氧化镁薄片的形貌、结构、成分以及热稳定性和比表面积等,结果表明,纳米氢氧化镁薄片的生长是一个成核-生长-组装过程,随着生长时间的延长,形貌从二维紧凑型结构演变成三维花状超结构,反应过程中液体-晶体和液-气界面的自由能作用使得纳米薄片趋向于垂直排列。此外,氢氧化镁纳米薄片薄膜的疏水性能也进行了研究。 相似文献
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单分散钛酸钡纳米晶的制备 总被引:3,自引:0,他引:3
采用溶剂热法制备出表面包裹油酸的单分散立方相钛酸钡纳米晶, 晶粒平均尺寸为6.0 nm, 采用TEM和XRD对其微结构进行了表征; 研究了醇的链长度、油酸用量和热处理温度等对钛酸钡的相组成和形貌的影响规律. 研究结果表明, 产物粒径较小, 粒度分布较窄, 单分散性较好, 其表面为非极性, 可溶于非极性试剂; 由于纳米晶表面由亲油性的长链烷基所覆盖, 与周围的水性环境不相容, 产生一定的斥力; 在重力和该斥力的共同作用下, 纳米晶可以有效地从液相环境中分离出来. 相似文献
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Shape apprearance and crystallite characterization of magnesium hydroxide at different hydrothermal tempera-tures have been investigated by SEM, XRD and DSC methods. The grain size, cell parameter and lattice distortion rate of powders under each condition were obtained. The results show that the grains had grown up, especially along the (001) surface as the hydrothermal temperature was raised, accompanying the shrinkage of lattice and the de-scending of distortion rate. These could be relate to the re-crystallization of Mg(OH)2, as well as the thermal dif-fusion of OH- with lower charges, resulting in good dispersion, high thermal decomposition temperature and en-thalpy of Mg(OH)2. Moreover, it is helpful for the increase of the retardant behavior of Mg(OH)2. 相似文献
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Controlled synthesis of single-crystalline Mg(OH)2 nanotubes and nanorods via a solvothermal process
Weiliu Fan Xinyu Song Weimin Zhang Haiyun Yu Xuejie Tan Guangxiang Cao 《Journal of solid state chemistry》2004,177(7):2329-2338
The synthesis of Mg(OH)2 one-dimensional (1D) nanostructures was systematically investigated in different solvents at various temperatures with Mg10OH18Cl2·5H2O nanowires as source materials. The results showed that the characters of the products, such as crystal size, shape, and structure, were strongly influenced by the solvent and temperature during the solvothermal process. 1D nanotubes of Mg(OH)2, with 80-300 nm outer diameter, 30-80 nm wall thickness, and several tens of micrometers in length were obtained by choosing bidentate ligand solvents such as ethylenediamine and 1,6-diaminohexane as the reaction solvent. But when using monodentate ligand pyridine as the reaction solvent, the obtained samples showed nanorods morphology. The Mg(OH)2 thus produced was analyzed by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), high-resolution electron microscopy (HRTEM), and selected-area electron diffraction (SAED). The possible growth mechanism of the 1D nanostructure Mg(OH)2 was discussed. 相似文献
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SUN Ling-na WANG Ke-li LUO Sheng-jun GUO Qing-rong HU Chang-wen 《高等学校化学研究》2007,23(5):508-510
β-Co(OH)2 and Mg(OH)2 nanoplates were synthesized via a facile template-free hydrothermal approach.The different conditions of preparation and catalytic properties of the products were studied and discussed.The products were characterized by X-ray diffraction,transmission electron microscopy,scanning electron microscopy,selected area electron diffraction(SAED),and gas chromatograph. 相似文献
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采用配位沉淀法制备出了Ni(OH)2样品,经XRD测试为β-Ni(OH)2,TEM测试结果表明其为平均粒径50nm左右的不规则的颗粒。将所制备的纳米Ni(OH)2按8wt%的比例在球镍中混合后制成电极,可使正极的比容量提高11%左右。热分析表明,纳米Ni(OH)2的电化学活性高于球镍的电化学活性。激光拉曼光谱的测试结果说明了8wt%混合后制成的纳米电极确实有较好的放电容量,同时也证实了用拉曼光谱可以表征电极材料的充放电 相似文献
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Yuanyuan Luo 《Journal of solid state chemistry》2007,180(7):2149-2153
Flower-like Ni(OH)2 nanoarchitectures have been synthesized through a one-step mild hydrothermal reaction with the aid of ethylenediamine in NiCl2 aqueous solution. The flower with the size of several micrometers in diameter is composed of the ultra-thin nanosheets of several nanometers in thickness. It was found the ethylenediamine is vital to the formation of the flower-like nanoarchitectures. The influence of the concentration of the ethylenediamine and the reaction temperature on the formation of the flowers was analyzed and the formation mechanism of the flowers was proposed. Such flower-like β-Ni(OH)2 nanoarchitectures will find potential applications in the fields, such as electrode, or will be used as a starting material to produce NiO, which is widely used in the magnetic, catalysts, sensor and electrochromic devices. 相似文献
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沉淀转化法制备的Co(OH)2的超级电容特性 总被引:11,自引:0,他引:11
Cobalt hydroxide, often used as an additive in nickel electrode, is rarely studied as active material for su-percapacitors. In this paper, the Co(OH)2 with the particle size less than 20nm by deposition transformation was synthesized. Its single electrode specific capacitance was measured to be 92F·g-1, and the electrode resistance was so low that the initial potential drop when discharging is unobvious even the discharge current increased to 200mA for a 1cm2 electrode. After ten thousand cycles, Co(OH)2 on the electrode changes to Co3O4 gradually, the resistance of the electrode does not increase much, while the specific capacitance increases to 133F·g-1 at 10mA。 相似文献
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通过调节溶液的pH值,在水热条件下合成出长径比为2-45的La(OH)3纳米棒. 对水热合成过程中间体的结构演变分析,发现高碱度有利于小尺寸晶核的形成,La(OH)3晶体结构的各向异性导致这些晶种沿着C轴方向生长,进而形成纳米棒结构. 将La(OH)3纳米棒前驱体于773 K焙烧可以得到长径比为2-20的La2O2CO3纳米棒. 随着长径比的增加,La2O2CO3纳米棒暴露的(110)晶面逐渐增加,La3+-O2-碱性位的数目也从0.08增加到0.24 mmol/g. 因此,在Claisen-Schmidt缩合反应中,La2O2CO3纳米棒催化剂上的反应速率随着长径比的增加而逐渐增大. 相似文献