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One-dimensional (1D) CoPt nanorods were synthesized by a galvanic displacement reaction. The morphology of the nanomaterials was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). Energy-dispersive X-ray spectroscopy (EDS) analysis confirmed the coexistence of Co and Pt in the 1D nanorods. Studies of cyclic voltammetry (CV) demonstrated that the 1D CoPt nanorods exhibit a better electrocatalytic property for CO oxidation than that of bulk Pt electrode does. In situ electrochemical FTIRS illustrated, for the first time, that the 1D CoPt nanorods display abnormal infrared effects (AIREs), which was previously revealed mainly on 2D film nanomaterials. 相似文献
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One-pot synthesis of hollow superparamagnetic CoPt nanospheres 总被引:1,自引:0,他引:1
Hollow metal nanospheres are of interest for a variety of academic and technological applications, including drug delivery, catalysis, plasmonics, and lightweight structural composites. Despite recent advances in synthesizing metal nanostructures with controlled morphologies, there are very few reports of hollow bimetallic nanospheres, although such systems promise to offer advantages over single-metal systems. Here, were report a one-pot synthetic strategy for accessing hollow CoPt nanospheres with a Co-Pt alloy structure. The approach utilizes an in situ Co template and exploits galvanic displacement reactions to selectively dissolve the Co core while depositing a Pt shell. The combination of reducing conditions and a polymer stabilizer appears to allow the Co and Pt to co-reduce and form a Co-Pt fcc alloy phase with a morphology that is templated by the sacrificial Co core. The hollow CoPt nanospheres, which show magnetic hysteresis at low temperatures, are thermally stable up to 300 degrees C. The approach, which adds to a growing toolbox of reactions that yield morphologically controlled magnetic CoPt and FePt nanomaterials, is likely to be general for a variety of alloy systems. 相似文献
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Shevchenko EV Talapin DV Schnablegger H Kornowski A Festin O Svedlindh P Haase M Weller H 《Journal of the American Chemical Society》2003,125(30):9090-9101
High quality CoPt(3) nanocrystals were synthesized via simultaneous reduction of platinum acetylacetonate and thermodecomposition of cobalt carbonyl in the presence of 1-adamantanecarboxylic acid and hexadecylamine as stabilizing agents. The high flexibility and reproducibility of the synthesis allows us to consider CoPt(3) nanocrystals as a model system for the hot organometallic synthesis of metal nanoparticles. Different experimental conditions (reaction temperature, concentration of stabilizing agents, ratio between cobalt and platinum precursors, etc.) have been investigated to reveal the processes governing the formation of the metal alloy nanocrystals. It was found that CoPt(3) nanocrystals nucleate and grow up to their final size at an early stage of the synthesis with no Ostwald ripening observed upon further heating. In this case, the nanocrystal size can be controlled only via proper balance between the rates for nucleation and for growth from the molecular precursors. Thus, the size of CoPt(3) nanocrystals can be precisely tuned from approximately 3 nm up to approximately 18 nm in a predictable and reproducible way. The mechanism of homogeneous nucleation, evolution of the nanocrystal ensemble in the absence of Ostwald ripening, nanocrystal faceting, and size-dependent magnetic properties are investigated and discussed on the example of CoPt(3) magnetic alloy nanocrystals. The developed approach was found to be applicable to other systems, e.g., FePt and CoPd(2) magnetic alloy nanocrystals. 相似文献
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《Electrochemistry communications》2008,10(4):514-518
Ordered metal (Co, Pt, and CoPt alloy) nanotube and nanowire structures were fabricated by a simple electroplating method in high aspect-ratio anodic aluminum oxide (AAO) membrane. The growth rate in pulse mode is always larger than that in constant-current mode, which represents that diffusion limitation exists in this electroplating condition. It is also found that the sputtered Au layer structure could influence the electroplating. Traditional nanowires could be fabricated in the template with a uniform Au layer as conducting contact. In case of unblocked AAO membrane, metal electroplating begins from the Au particles which were attached inside the holes during the sputtering step and produces metal nanotubes. Pt and CoPt nanotubes could be easily prepared by this method and might be applied as catalyst and magnetic material. 相似文献
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溶胶-凝胶法是常见的制备金属氧化物的方法之一。在溶胶-凝胶法中,各种反应物能达到分子级的均匀混合,因此能制备成份复杂的氧化物材料。目前,溶胶-凝胶法也应用于设计与制备金属纳米材料,特别是合金纳米颗粒。例如,溶胶-凝胶法能应用于制备CoPt、FePt等磁性纳米合金材料以及CoCrCuNiAl高熵合金纳米材料,以及物相结构为有序相的Cu3Pt合金纳米材料。本文综述溶胶-凝胶法设计制备金属纳米材料的研究进展,包括溶胶-凝胶法实施的基本步骤、该方法在制备金属纳米材料方面的具体应用,并着重论述采用热力学计算设计金属及化合物的基本原理。该基本原理包括计算金属氧化物与还原性气体如氢气的还原反应的吉布斯自由能的变化量、金属氧化物的标准电极电位(不同于金属离子的标准电极电位)。最后探讨溶胶-凝胶法设计制备金属纳米材料存在的问题以及后续可能的发展方向。 相似文献
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Park JI Kim MG Jun YW Lee JS Lee WR Cheon J 《Journal of the American Chemical Society》2004,126(29):9072-9078
The structure, magnetism, and phase transition of core-shell type CoPt nanoparticles en route to solid solution alloy nanostructures are systematically investigated. The characterization of Co(core)Pt(shell) nanoparticles obtained by a "redox transmetalation" process by transmission electron microscopy (TEM) and, in particular, X-ray absorption spectroscopy (XAS) provides clear evidence for the existence of a core-shell type bimetallic interfacial structure. Nanoscale phase transitions of the Co(core)Pt(shell) structures toward c-axis compressed face-centered tetragonal (fct) solid solution alloy CoPt nanoparticles are monitored at various stages of a thermally induced annealing process and the obtained fct nanoalloys show a large enhancement of their magnetic properties with ferromagnetism. The relationship between the nanostructures and their magnetic properties is in part elucidated through the use of XAS as a critical analytical tool. 相似文献
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运用电位置换结合化学还原方法制备了两种不同结构的CoPt纳米棒材料,一种为实心结构(CoPt-a),一种为空心结构(CoPt-b).采用透射电镜(TEM)和能量散射光谱(EDS)研究了其形貌和组成.在5和300K下测试了两种纳米棒的磁学性能.结果显示,CoPt-a和CoPt-b纳米棒在5K时的矫顽力分别为6.5和9.3A·m-1,温度升至300K时,两种结构CoPt纳米棒矫顽力均减小为0A·m-1.场冷曲线(FC)和零场冷曲线(ZFC)结果表明两种结构的CoPt纳米棒均表现出超顺磁性,阻塞温度(TB)分别为10.0和9.0K.两种CoPt纳米棒组成、结构等不同可能是引起其矫顽力、磁化强度和阻塞温度差异的主要原因. 相似文献
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Yaxin Wang Xiaolong Zhang Yang Liu Yuhong Jiang Yongjun Zhang Jinghai Yang 《Journal of Sol-Gel Science and Technology》2014,70(3):528-533
CoPt nanoparticles with various Ag contents were synthesized by sol–gel technique. L10 CoPt alloy phase was formed after annealing at 700 °C. The coercivity (Hc) increased when the Ag content increased from 0 to 15 at.%. And Hc decreased when the Ag content was over 15 at.%. A certain amount of Ag could enhance the ordering degree of CoPt nanoparticles and improve the magnetic properties. When the Ag addition was more than 15 at.%, the deteriorated magnetic properties were ascribed to the decrease of ordering degree. 相似文献
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One‐Pot Synthesis of Pt–Co Alloy Nanowire Assemblies with Tunable Composition and Enhanced Electrocatalytic Properties
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Dr. Bao Yu Xia Hao Bin Wu Nan Li Ya Yan Prof. Xiong Wen Lou Prof. Xin Wang 《Angewandte Chemie (International ed. in English)》2015,54(12):3797-3801
Three‐dimensional (3D) Pt‐based alloy nanostructures composed of one‐dimensional (1D) nanowires/nanorods have recently attracted significant interest as electrocatalysts. In this work, we report an effective solvothermal method for the direct preparation of 3D Pt–Co nanowire assemblies (NWAs) with tunable composition. The composition‐ and structure‐dependent electrocatalytic performance is thoroughly investigated. Because of the bimetallic synergetic effect and unique structural advantage, the as‐prepared 3D Pt3Co NWA outperforms commercial Pt/carbon and Pt black catalysts and even 3D Pt NWA. The electrochemical results demonstrate that the 3D Pt3Co NWA is indeed a promising electrocatalyst with enhanced catalytic activity and improved durability for practical electrocatalytic applications. 相似文献
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采用电沉积和溶剂热相结合的方法,以树枝状金属Cd颗粒为模板和前驱体,在乙二胺溶剂中以六亚甲基四胺(HMTA)为表面修饰剂,制备出具有三维阵列结构的树枝晶CdS。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)结合X射线能谱仪(EDS)等对样品的物相、形貌、元素组分和结构进行了分析。结果表明:在溶剂热反应过程中,当不加入HMTA时,得到的产物是无序的CdS纳米线;而在HMTA的作用下,则生成的是具有三维阵列结构的树枝晶CdS;通过分析溶剂热反应过程中的化学反应,并结合产物形貌演变规律,提出了具有三维阵列结构的树枝晶CdS的形成机理。光催化性能测试表明具有三维树枝晶CdS纳米阵列在可见光照射下表现出良好的光催化活性。 相似文献
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Synthesis of CoPt nanorods in ionic liquids 总被引:7,自引:0,他引:7
Cobalt platinum nanorods, hyperbranched nanorods, and nanoparticles were synthesized in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [BMIM][Tf2N], ionic liquid though the thermal reduction of platinum acetylacetonate, and cobalt acetylacetonate at 350 degrees C in the presence of cetyltrimethylammonium bromide (CTAB). It was found that the morphology, composition, and crystal phase of the resultant CoPt alloy nanomaterials could be controlled by changing the concentration and molar ratio of platinum and cobalt reactant precursors. 相似文献
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Liu H Li Y Xiao S Gan H Jiu T Li H Jiang L Zhu D Yu D Xiang B Chen Y 《Journal of the American Chemical Society》2003,125(36):10794-10795
The synthesis of anthracene (AN) nanowires and perylene (PY) nanorods on the basis of solid-phase organic reactions under controlled conditions is discussed, and the structures are confirmed by SEM, TEM, and XRD. The dimension-dependent emission properties of the AN nanowires and PY nanorods is observed. This approach is expected to form a new general route for the controlled morphosynthesis of organic molecular materials in restricted dimensions, with controlled size and shape, the solid-state physical properties of which are of great interest. It should have outstanding potential in providing customized 1D nanomaterials for a broad range of applications for molecule devices and nanoscience and is expected to be applicable other functionalized nanomaterials (i.e., organic, inorganic, and polymer). 相似文献
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采用电沉积和溶剂热相结合的方法,以树枝状金属Cd颗粒为模板和前驱体,在乙二胺溶剂中以六亚甲基四胺(HMTA)为表面修饰剂,制备出具有三维阵列结构的树枝晶CdS。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)结合X射线能谱仪(EDS)等对样品的物相、形貌、元素组分和结构进行了分析。结果表明:在溶剂热反应过程中,当不加入HMTA时,得到的产物是无序的CdS纳米线;而在HMTA的作用下,则生成的是具有三维阵列结构的树枝晶CdS;通过分析溶剂热反应过程中的化学反应,并结合产物形貌演变规律,提出了具有三维阵列结构的树枝晶CdS的形成机理。光催化性能测试表明具有三维树枝晶CdS纳米阵列在可见光照射下表现出良好的光催化活性。 相似文献
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Hu MJ Lu Y Zhang S Guo SR Lin B Zhang M Yu SH 《Journal of the American Chemical Society》2008,130(35):11606-11607
A simple solvothermal method has been discovered to synthesize single-walled flux-closure Ni-Co magnetic alloy nanorings in high yield, which are directly fabricated in a reaction solution and able to chronically exist in solution. 相似文献
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Colloidal synthesis and self-assembly of CoPt(3) nanocrystals 总被引:3,自引:0,他引:3
Shevchenko EV Talapin DV Rogach AL Kornowski A Haase M Weller H 《Journal of the American Chemical Society》2002,124(38):11480-11485
Reduction of platinum acetylacetonate and thermodecomposition of cobalt carbonyl in the presence of 1-adamantanecarboxylic acid were employed in different coordinating mixtures to produce monodisperse, highly crystalline CoPt(3) nanoparticles. The mean particle size can be varied from 1.5 to 7.2 nm by controlling the reaction conditions and the type of coordinating mixture. As-synthesized CoPt(3) particles represent single crystal domains and have chemically disordered face-centered cubic (fcc) structure. Nearly spherical CoPt(3) nanocrystals were found to assemble into two- (2D) and three-dimensional (3D) structures. An AB(5) type superlattice is observed by TEM after mixing two nanoparticle samples with different mean sizes. Slow precipitation led to the formation of facetted colloidal crystals with sizes up to 20 microm. 相似文献