电弧法制备洋葱状富勒烯的工艺研究

运用纳米Bi2O3微粒作催化剂，在电弧放电条件下，进行了纳米洋葱状富勒烯大量合成的研究。并用透射电镜对产物的形貌、结构进行了观察与分析。结果表明：纳米洋葱状富勒烯的石墨化程度很高，且直径均匀(约为25nm)，结构较完善；同时伴有单核纳米洋葱状富勒烯向多核纳米洋葱状富勒烯的转变。为洋葱状富勒烯的宏量制备提供了有利线索。     

电弧放电条件下内包金属洋葱状富勒烯生成机理的研究

采用电弧法制备内包纳米金属微粒的洋葱状富勒烯.通过XRD、SEM和HRTEM对样品进行结构表征和分析,讨论影响纳米洋葱状富勒烯生成的因素.结果表明:可以宏量地制备内包金属微粒的NSOFs,且晶化程度很高;优化工艺参数可获得合适的气相温度及温度梯度,有利于NSOFs的生成;建立了汽-液-固(VLS)生长模型以解释其形成机理.     

水下放电制备内包金属洋葱状富勒烯的研究

以二茂铁和纳米Ni粒子为催化剂,在水下放电条件下,制备了内包金属洋葱状富勒烯(Onion-like Fullerenes:OLFs),利用高分辨透射电镜(HRTEM)和X射线衍射(XRD)对所得产物进行了表征.结果表明:二茂铁和纳米Ni粒子均可催化得到内包金属洋葱状富勒烯,内包Fe洋葱状富勒烯直径分布在5～50nm之间,内包Ni洋葱状富勒烯直径分布在10～35nm之间.     

金属对炭黑转化为洋葱状中空结构纳米碳的影响

研究了炭黑分别在 Fe、Co、Ni 三种金属化合物作用下的催化转化行为, 以期使炭黑质点中不连续的无规则小石墨片层重新组装、构筑成洋葱状中空结构纳米碳. 采用透射电子显微镜(TEM)、高分辨透射电子显微镜(HRTEM)、X射线衍射(XRD)和Raman光谱分析表征了炭黑及其催化炭化产物的微观形貌和结构. 结果表明: 尽管三种金属催化剂均可通过溶碳-析出机制形成过渡态碳包覆纳米金属颗粒, 继而构筑成由准球形同心石墨壳层组合的洋葱状中空结构纳米碳, 但三种金属催化剂显示不同的催化效果, 终碳产物的形态和纯度差异较大, 其中以Fe 的催化效果最好.     

Fe/洋葱状富勒烯的化学修饰及润滑性研究EI北大核心

采用化学气相沉积(CVD)法制备了内包金属Fe/洋葱状富勒烯,利用高分辨透射电镜(HETRM)、X-射线衍射(XRD)和傅立叶红外(FT-IR)等对产物的结构和形貌进行了表征;运用硬脂酸对Fe/洋葱状富勒进行化学修饰;着重讨论硬脂酸修饰后Fe/洋葱状富勒烯作为润滑油添加剂的分散性和稳定性。结果表明所制备的Fe/洋葱状富勒烯颗粒均匀,通过酯化反应Fe/洋葱状富勒烯能够被硬脂酸包覆,显著提高了Fe/洋葱状富勒烯在润滑油中的分散性和稳定性。在MRS-10A型四球摩擦试验机上考察了Fe/洋葱状富勒烯作为机油添加剂的润滑性能。     

纳米洋葱状富勒烯的研究现状及前景

通过述评纳米洋葱状富勒烯的结构、制备、生长机理、纯化、修饰及性能,指出:纳米洋葱状富勒烯具有独特的中空笼状及同心壳层结构,是富勒烯家族的一个重要成员,具有许多特殊性能,有望在能源材料、高性能、高温耐磨材料、超导材料和生物医用材料等领域得到广泛的应用.     

碳包Ni纳米晶的形成及其特性

用直流碳弧法制备出碳包Ni金属纳米晶.在石墨阳极复合棒中掺入不同组份的Ni，研究其对碳包Ni纳米晶，富勒烯等碳微团特性的影响结果表明：碳包Ni纳米晶含Ni和石墨，不含碳化物和氧化物；纳米品数量随Ni增加而增加．而纳米晶的粒径出现极值；Ni催化碳微团石墨化并使C60／70产率下降；碳包Ni金属纳米晶单位质量的饱和磁化强度随Ni的增加而增加     

催化剂种类对纳米洋葱状富勒烯形成的影响

研究了相同电弧放电条件下,不同催化剂(Fe、Al)掺杂对洋葱状富勒烯形成的影响.用高分辨透射电子显微镜(HRTEM)和X-射线衍射(XRD)对产物进行了观察与表征.结果表明,Fe作催化剂形成的洋葱状富勒烯产量和质量都优于Al作催化剂的情况,Fe的催化活性较Al的高,是制备洋葱状富勒烯的一种更加有效的催化剂.     

环己烷制备内包金属洋葱状富勒烯的研究

采用CVD法制备了内包金属洋葱状富勒烯(Onion-like Fullerenes,OLFs),并通过XRD、SEM、EDS和TEM等手段对产物进行了结构表征.结果表明,以二茂铁溶于环己烷中制成的溶液为碳源,在900℃经化学气相沉积制备出的内包金属OLFs呈球状或准球状,直径在10～60 nm之间,包含有11.6 wt?,石墨化程度较高.     

纳米洋葱状富勒烯的研究进展及动向

评述了纳米洋葱状富勒烯的研究发展过程和动向，论述了该物质的各种制备方法及其工艺，并对各种制备工艺进行了分析和探讨性研究，在此基础上比较论述了每种方法的优缺点，展望了纳米洋葱状富勒烯基础研究，宏量制备和应用研究的发展趋向。     

Catalytic Functions of Metal Nanoparticles on Polymerization of Acetylene

New spiral nano-fibers were synthesized by a polymerization process of acetylene with metal nanoparticles as catalysts which were prepared by a hydrogen arc plasma method. The microstructures, conductive property of the nano-fibers and the effects of different nanoparticles(catalysts) on the microstructures of the fibers were studied.     

Surface enhanced Raman scattering spot tests: a new insight on Feigl's analysis using gold nanoparticles

Traditional Feigl's spot tests can be greatly improved with the aid of gold nanoparticles and Raman probes, by monitoring the changes in the surface enhanced Raman scattering (SERS) of the analytes directly applied on a filter paper previously impregnated with the selective organic reagent. As a proof of concept, diphenylthiocarbazone (dithizone) was treated with citrate stabilized gold nanoparticles and employed in paper spot tests for a variety of transition and heavy metal ions. Below 10(-5) mol L(-1), only mercury(II) ions were able to displace the dithizone molecules from the "coordination shell" of the gold nanoparticles, leading to a systematic decay of the Raman signals. Because of the huge enhancement of the dithizone vibrational peaks, the SERS spot tests allowed the detection of picograms of Hg(2+) ions.     

The polymerizations of alkylsilane and bis-(γ-triethoxysilylpropyl)-tetrasulfide catalyzed by copper nanoparticles and the effects of transition metal ions on the polymerizations of alkylsilane catalyzed by silver nanoparticles

Poly(vinylpyrrolidone) (PVP)-capped copper nanoparticles synthesized by solvent-based polyol reduction were found to be effective catalysts for the polymerization of octadecylsilane and bis-(γ-triethoxysilylpropyl)-tetrasulfide. Comparing with PVP-capped silver nanoparticles, copper nanoparticles exhibited different catalytic activity, and the polymerization products also showed different morphologies. The effects of transition metal ions on the polymerization of octadecylsilane catalyzed by PVP-capped silver nanoparticles were also investigated. It was found that transition of metal ions not only had strong effects on the morphologies of the products of polymerizations, but also resulted in the disappearance of silver oxide. The products were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) and X-ray powder diffraction (XRD).     

Enhanced activity and stability of Cu-Mn and Cu-Ag catalysts supported on nanostructured mesoporous CeO2 for CO oxidation

Cu, Mn and Ag nanoparticles are loaded on nanostructured mesoporous CeO2 as catalysts for CO oxidation. The Cu/CeO2 catalyst exhibits an obvious deactivation after the stability test at 95 degrees C for 60 h. This is caused by carbon deposition as confirmed by FTIR spectroscopy, Raman spectroscopy and thermogravimetry-differential scanning calorimetry-mass spectroscopy (TG-DSC-MS) analysis. It is found that the Cu-Mn or Cu-Ag binary metal catalysts supported on the nanostructured CeO2 exhibit much improved activity and stability in CO oxidation. In ease case, carbon deposition is absent in the similar stability test, due to enhanced oxygen adsorption property.     

Gold/palladium and silver/palladium colloids as novel metallic substrates for surface-enhanced Raman scattering

New surface-enhanced Raman scattering (SERS) substrates, composed of gold or silver colloidal nanoparticles doped with palladium, were prepared. These novel colloids are stable and maintain a satisfactory SERS efficiency, even after long aging. The interest in doping the coinage metal nanoparticles with palladium is due to the well-known catalytic activity of this metal. Transmission electron microscopy (TEM) and ultraviolet-visible absorption spectroscopy were used to characterize the shape and size of the metal particles. It was found that these bimetallic colloidal nanoparticles have a core-shell structure, with gold or silver coated with palladium clusters.     

Surface-enhanced Raman scattering of carbon nanotubes by decoration of ZnS nanoparticles

ZnS nanoparticles anchored on the single-walled carbon nanotubes (SWNTs) were fabricated by a chemical vapor deposition (CVD) method. The CVD method shows no selectivity for growth of ZnS nanoparticles on types and defects of the SWNTs, and thus ensures the uniform decoration of all SWNTs on the substrate. ZnS nanoparticles with a diameter of 10 nm were decorated on the SWNTs surface with an interparticle distance of about 20 nm. This method provides the possibility to realize the optimal configurations of ZnS nanoparticles on SWNTs for obtaining surface-enhanced Raman spectroscopy (SERS) of SWNTs. Investigations of mechanism reveal that charge transfer (a small amount of excitation electrons) from ZnS nanoparticles to SWNTs weakly affects Raman intensity, and the coupled surface plasmon resonance (SPR) formed from plenty of excitation electrons on the surface of ZnS nanoparticles contributes to the strong surface enhancement. It would be an alternative approach for SERS after metal (normally gold or silver) nanoparticles' decoration on the SWNTs surface.     

A simple and facile method to synthesize Co3O4 nanoparticles from metal benzoate dihydrazinate complex as a precursor

This report describes the novel synthesis of cobalt oxide (Co₃O₄) nanoparticles from corresponding metal benzoate dihydrazinate complex as a precursor followed by thermal decomposition. Transmission electron microscopy (TEM) revealed nearly uniform nanoparticles with an average particle size of around 20 nm. X-ray diffraction (XRD) and selected-area electron diffraction (SAED) demonstrated that the nanoparticles were composed of pure cubic phase polycrystalline Co₃O₄. The nanoparticles were also confirmed by Raman spectroscopy. In principle, this simple and inexpensive synthetic procedure can be employed to prepare other transition metal oxide nanoparticles.     

Effect of Co and Ni nanoparticles formation on carbon nanotubes growth via PECVD

The effect of cobalt (Co) and nickel (Ni) nanoparticle catalysts on the growth of carbon nanotubes (CNTs) were studied, where the CNTs were vertically grown by plasma enhanced chemical vapour deposition (PECVD) method. The growth conditions were fixed at a temperature of 700 °C with a pressure of 1000 mTorr for 40 minutes with various thicknesses of sputtered metal catalysts. Only multi-walled carbon nanotubes are present from the growth as large average diameter of outer tube (～10–30 nm) were measured for both of the catalysts used. Experimental results show that high density of CNTs was observed especially towards thicker catalysts layers where larger and thicker nanotubes were formed. The nucleation of the catalyst with various thicknesses was also studied as the absorption of the carbon feedstock is dependent on the initial size of the catalyst island. The average diameter of particle size increases from 4 to 10 nm for Co and Ni catalysts. A linear relationship is shown between the nanoparticle size and the diameter of tubes with catalyst thicknesses for both catalysts. The average growth rate of Co catalyst is about 1.5 times higher than Ni catalyst, which indicates that Co catalyst has a better role in growing CNTs with thinner catalyst layer. It is found that Co yields higher growth rate, bigger diameter of nanotube and thicker wall as compared to Ni catalyst. However, variation in Co and Ni catalysts thicknesses did not influence the quality of CNTs grown, as only minor variation in I_G/I_D ratio from Raman spectra analysis. The study reveals that the catalysts thickness strongly affects not only nanotube diameter and growth rate but also morphology of the nanoparticles formed during the process without influencing the quality of CNTs.     

Gold nanoparticles–graphene hybrids as active catalysts for Suzuki reaction

Graphene was successfully modified with gold nanoparticles in a facile route by reducing chloroauric acid in the presence of sodium dodecyl sulfate, which is used as both a surfactant and reducing agent. The gold nanoparticles–graphene hybrids were characterized by high-resolution transmission electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, X-ray diffraction and energy X-ray spectroscopy. We demonstrate for the first time that the gold nanoparticles–graphene hybrids can act as efficient catalysts for the Suzuki reaction in water under aerobic conditions. The catalytic activity of gold nanoparticles–graphene hybrids was influenced by the size of the gold nanoparticles.