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1.
以氯化钴和黄磷为主要原料,以十六烷基三甲基溴化铵(CTAB)为结构导向剂,采用微波水热法制备了一维磷化钴(Co_2P)纳米线。研究了表面活性剂及其加入量对合成Co_2P相结构和形貌的影响及电化学性能。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)对产物的物相和显微结构进行表征。结果表明:引入表面活性剂均可以使试样中生成一维Co_2P纳米结构,添加CTAB的试样中生成了大量的Co_2P纳米线,其直径约为50~200 nm,产率和长径比均随着CTAB加入量的增加而增加。电化学性能结果表明,Co_2P纳米线具有赝电容特性,循环稳定性较好,1000次循环后比电容保持率为68%。  相似文献   

2.
水热法合成超长γ-MnOOH和α-MnO2亚微米/纳米线   总被引:1,自引:0,他引:1  
采用水热法,以KMnO4和MnSO4为前驱物,使用十六烷基三甲基溴化胺(CTAB)、聚乙二醇(PEG)等表面活性剂,通过对反应物比例、温度、反应时间及表面活性剂等条件的调控,分别合成了7-MnOOH、α-MnO2超长纳米线及亚微米/纳米棒。分别采用X射线衍射分析(XRD)、扫描电子显微镜(SEM)对产物结构及形貌进行了表征。结果表明,MnOOH为γ相,改变条件可分别得到直径约100nm的超长纳米线和直径约为200nm的亚微米/纳米棒;不同条件所得MnO2均为α相、分别为直径约100nm,长度超过20μm纳米线和直径小于100nm的放射状棒束。  相似文献   

3.
在本文中,我们通过两步法合成了具有核壳结构的CoO/NiO纳米线。透射电子显微镜的结果显示,CoO纳米线被NiO的纳米片层结构紧密包覆,同时该样品具有独特的多孔结构。由于其特殊结构,该样品用于超级电容器电极材料显示了优异的电容性能(当电流密度为1 A g-1时,其比电容能够达到708 F g-1),同时该样品显示了良好的倍率特性以及循环稳定性(当循环1000个周期后,其电容保持力为80 %),其电容性能明显优于单组份样品。这主要是由于CoO纳米线和NiO纳米片相比于单一组分能够为氧化还原反应提供更多的活性位点,这种协同作用有助于提高材料整体的比电容以及电化学稳定性。  相似文献   

4.
采用电化学沉积法,在氧化铝模板中制备了不同直径的Co纳米线的高度有序阵列。纳米线的结构和磁学特性分别用透射电子显微镜(TEM),扫描电子显微镜(SEM),X射线衍射(XRD)仪和振动样品磁力计(VSM)测试。结果表明,Co纳米线是以fcc和hcp结构同时存在。磁学性质研究表明,这种阵列具有较强的垂直磁各向异性。直径对纳米有序阵列磁学特性的影响研究表明,当直径超过100nm后,Co纳米线磁学性质与块体Co已经没有什么区别。  相似文献   

5.
通过水热法成功合成Co3O4/Cu O复合物,并探索十六烷基三甲基溴化铵(CTAB)和聚乙烯吡咯烷酮(PVP)对其形貌和性能的影响。用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和氮气吸附-脱附测试表征其微观结构和表面形貌。采用循环伏安、恒流充放电和交流阻抗测试等方法研究样品的电化学性能。结果表明,多孔Co3O4/Cu O-CTAB纳米片具有最好的电化学性能,在电流密度1 A/g下的比容量达398 F/g,而在10 A/g时其比容量仍能保持90%。此外,该复合物具有很好的循环稳定性,在2000次循环后容量几乎没有衰减。  相似文献   

6.
采用化学共沉淀法制备了可以在强碱性溶液中稳定存在的α—Ni(OH)2,比较了物理添加Co粉、晶格掺杂Co^2+以及表面包覆Co(OH)2等Co的不同添加方式对α-Ni(OH)2电化学性能的影响。利用X射线衍射(XRD)对电极循环过程中的结构变化进行了表征,采用恒流充放电测试方法研究了所制备的α-Ni(OH)2在不同电流密度下的放电比容量。结果表明3种方式添加Co都可以在一定程度上提高样品的循环稳定性和大电流放电比容量,其中以表面包覆Co(OH)2的方式效果最为明显。  相似文献   

7.
Fe替代Co对AB5型贮氢合金电化学性能和相结构的影响   总被引:1,自引:1,他引:1  
研究了Fe替代C0对Mm(NiMnSiAl)4.3Co0.6-xFex(x=0,0.2,0.4,0.6)贮氢合金电化学性能和相结构的影响。研究结果表明:Fe替代Co使合金的放电容量降低,但使合金的循环稳定性得到改善;合金具有双相结构,主相为CaCu5型相,还有少量的第二相Ce2Ni7相,随着Fc替代量的增加,第二相没有明显变化,但合金的点阵常数和晶胞体积略有增加,这是Fe替代Co使合金循环稳定性得以改善的一个主要原因。  相似文献   

8.
用共沉淀还原扩散法制备了不同化学计量比的LaMg2Ni9-xCox(x=0.3-6.0)和M/Mg2Ni9-xCox(x=0.3-4.5)稀土镁基储氢电极合金。电化学测试结果表明:制得的合金活化性能良好;在Co含量x逐渐增大的过程中,合金的活化次数没有发生明显的变化,合金的放电容量逐渐减小,合金的循环稳定性逐渐增强。混合稀土合金比纯镧合金的活化次数多、放电量小,但是循环稳定性好。合金结构分析表明,合金主相为MgNi2相和LaNi5相,随着Co含量增加,LaCo5相和LaCo3相含量增加。  相似文献   

9.
为了提高La-Mg-Ni系(PuNi3)型贮氢合金的电化学循环稳定性,在La2Mg(Ni0.85Co0.15)9合金中加入微量Cr,用铸造及快淬工艺制备了La2Mg(Ni0.85Co0.15)9Crx(x=0,0.1,0.2)贮氢合金.分析测试了铸态及快淬态合金的电化学性能及微观结构,研究了Cr对铸态及快淬态合金微观结构及电化学性能的影响.结果表明,铸态及快淬态合金具有多相结构,包括(La,Mg)Ni3相(PuNi3结构)),LaNi5相和一定量的LaNi2相.快淬对合金的相组成没有影响,但使合金的相丰度产生变化.Cr的加入提高了铸态及快淬态合金的循环稳定性,但使合金的容量下降.合金的循环寿命随淬速的增加而增加,铸态及快淬态合金均有优良的活化性能.  相似文献   

10.
以P123为表面活性剂,采用软模板法合成MnO2/CNT纳米复合材料。采用X射线衍射、热重和差热分析、傅立叶变换红外光谱分析和高分辨率透射电子显微镜对样品进行表征。结果表明,样品为弱结晶的α-MnO2,直径约10nm,长30?50nm,它们附着在碳纳米管壁上。样品的电化学性能通过组成Li-MnO2进行电池充放电和电化学阻抗测试(EIS),与纯二氧化锰相比,MnO2/CNT纳米复合材料具有更大的初始容量275.3mA·h/g和更好的倍率和循环性能。  相似文献   

11.
One-dimensional (1D) cadmium sulfide (CdS) nanostructures with various aspect ratios were successfully synthesized by a diphenylthiocarbazone (dithizone)-assisted solvothermal method. The results showed that the dithizone-assisted synthesized samples had larger aspect ratio than that prepared in the absence of dithizone, and CdS nanowires with the highest aspect ratio were obtained with an appropriate dithizone amount (0.03 g/50 ml ethylenediamine in the present system). All the 1D CdS nanostructures were in hexagonal wurtzite phase. The as-synthesized large-scale CdS nanowires were in diameters ranging from 70 to 80 nm, length up to 20 μm, and aspect ratios of 250-285. Further characterization indicated that the CdS nanowires were single crystalline with a preferential growth orientation of [0 0 2], c-axis. Two optical absorption peaks were observed at about 488 nm and 502 nm for the CdS nanowire sample with high aspect ratio in the optical absorption spectroscopy, which could be attributed to the nanometer effect of nanowires. It was found that the additive dithizone was a crucial factor in controlling the morphology and optical properties of the 1D CdS nanostructures. The growth mechanism of 1D CdS nanostructure and the effects of dithizone in the present system were discussed.  相似文献   

12.
利用多孔阳极氧化铝模板辅助法,在Co电解液和CdSe电解液的双槽体系中用直流电沉积法交替沉积合成一维多段Co-CdSe金属-半导体异质结纳米线。异质结纳米线的形貌、结构、磁学及光学特性分别用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、振动样品磁强计(VSM)、紫外可见分光光度计(UV-Vis)以及光致发光光谱仪(PL)进行表征。结果表明,Co-CdSe异质结纳米线分层明显,且同时以面心立方结构存在。Co-CdSe异质结纳米线拥有与单质金属Co纳米线相同的磁矫顽力,同时,异质结纳米线也表现优异的光学性能。  相似文献   

13.
采用微生物吸附-化学还原法,以大肠杆菌(ECCs)为模板、十六烷基三甲基溴化铵(CTAB)为保护剂、抗坏血酸(AA)为还原剂制备金钯纳米线(Au-Pd NWs),考察不同金钯摩尔比对合成金钯纳米材料的影响,并通过SEM、TEM、XRD等技术进行了表征,研究其形成机理。结果表明,吸附还原作用使ECCs在短时间内还原生成了少量Pd(0)和Au(0),大量的钯离子和金离子聚集在ECCs表面周围;还原剂AA的加入使ECCs表面成为优先成核位点,菌体表面基团与晶核相互作用阻止其迁移;在CTAB的作用下,菌体表面的纳米颗粒逐渐形成链状纳米中间结构,中间结构通过Ostwald熟化作用进一步形成Au-Pd纳米线。通过ECCs和CTAB协同作用,有利于一维纳米结构的生长。  相似文献   

14.
《Scripta materialia》2004,50(1):19-23
Two different morphologies of Co nanostructures, such as hollow nanotubes and nanowires composed of nanowhiskers, have been prepared in a controllable fashion by using a pore-wall modified alumina membrane and adjusting electrodeposition parameters. The mechanism of formation of the Co nanostructures was also discussed.  相似文献   

15.
NiCo alloy nanowires have been fabricated by electrodeposition using an anodized aluminum oxide (AAO) template. Single-crystalline and polycrystalline alloy nanowires have been obtained, and their microstructure was strongly dependent on the deposition conditions (current density and composition). In addition, unique nanostructures have been observed in NiCo alloy nanowires. Bamboo or layer structures were found for 15 and 25 at.% Co, respectively. The investigation of the mechanisms shows that these particular structures are related to the different diffusion rates of Ni and Co on the surface of the AAO template. The work demonstrates that as well as single-crystalline and polycrystalline nanowires, other unique nanostructures (layered and bamboo in this work) can be achieved through careful control of the preparation conditions.  相似文献   

16.
以阳极氧化铝为模板通过电泳沉积法制备Zn0.95Co0.05O纳米线和纳米管,并对电泳沉积法制备纳米线(管)的机理进行研究。系统的结构表征表明所得的纳米管和纳米线是由8~15nm的纤锌矿纳米晶构成的多晶结构,Co2+离子以代位掺杂形式掺入晶格,取代了晶格中的Zn2+离子。磁性表征显示制备的纳米线和纳米管具有室温铁磁性。由于Co在纳米线(管)中表面择优分布,纳米管的磁性明显高于纳米线。  相似文献   

17.
We have synthesized Cu nanowires via a simple process using both thermal evaporation and CuCl powders. In this method, complicated processes and special instruments are not required to synthesize Cu nanostructures. In addition, we have used commercial CuCl powders as a precursor. There have been no reports on the preparation of Cu nanostructures using simple instruments together with a commercial source material as in this study. Cu nanostructures of various morphologies were formed at relatively low temperature. The microstructure of the Cu nanostructures was investigated using HRTEM images and SAD pattern analysis.  相似文献   

18.
Biotemplating is an emerging, unique approach for the synthesis and organization of the organic or inorganic materials into well-defined nanostructures. In this article, conducting polymer polypyrrole (PPy) nanowires were electrochemically synthesized using a protein molecule, gelatin, as a template. The morphologies, microstructures, chemical compositions, and electrochemical performances of the obtained nanowires were investigated in detail. It was found that the gelatin played an important role in the formation of the PPy nanowires and the morphologies of the nanowires were closely related to the electrodes used. This work not only extended the application of gelatin to the synthesis of the conducting polymer nanowires, but also presented a simple and useful route to the fabrication of PPy nanowires with different length, from normal size to superlong size.  相似文献   

19.
Mesoporous iron phosphates were synthesized using sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) as surfactants. The material synthesized in the presence of SDS was not applied as a positive electrode active material of a lithium battery. The results show that the obtained FePO4 has a mesoporous structure with a specific surface area of 70 m2 g?1 and a dominant pore diameter of 3 nm. Those mesoporous were characterized by different microstructural and electrochemical analyzes. Among the materials studied under different conditions, those calcined at 450°C preserve mesoporous structures and exhibit the best electrochemical performance when used as active materials of the positive electrodes of lithium batteries. Effectively, a relatively high specific capacity of 135 and 122 mAh g?1 was registered at C/20 collected experimentally by the samples synthesized in the presence of SDS and CTAB, respectively.  相似文献   

20.
Zn0.95Co0.05O nanotubes, as well as nanowires, were controllably synthesized by electrophoretic deposition method using anodic aluminum oxide (AAO) as template, and the mechanism of electrophoretic deposition was discussed. Careful characterization indicates that the prepared nanotubes and nanowires are of poly-crystal wurtzite structure and composed with 8–15 nm nano-crystals. The doped Co2+ occupied the Zn2+ sites in the ZnO lattice. Magnetic investigation indicates that the obtained nanotubes and nanowires are of room-temperature ferromagnetic. The magnetism of the nanotubes is much higher than that of the nanowires for the surface-preferential Co distribution.  相似文献   

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