Decoration Of C₆₀ Nanorod With Nickel And Its High Pressure Study

As a representative member of carbon nanomatereial family, C₆₀ has been the subject of numerous studies due to its special molecule since its discovery. it has been investigated in various configurations such as films powders, bulk single crystals, and composites with metals, ceramics, and polymer matrices which shows outstanding performance in the field of novel superhard material, superconductivity, optics, catalysis etc. One-dimensional C₆₀ has also attracted much attention due to their potential applications in the field of nanometer scale devices, the preparation of highly crystalline C₆₀ with a specified geometry is of great interest and is a challenging topic.We have synthesized C₆₀ nanorods by a very facile solution method. The nanorods obtained are highly crystalline and single phase, and the nanorods with different diameters and length-to-diameter ratios can be controlled by adjusting growth conditions. This result motivated us to further study the fabrication of novel composite C₆₀ nanorod with other materials and to modify their physical properties. We studied the polymer matrices composed by C₆₀ nanorod and nickel, the nickel-coated carbon material has been an attractive topic. The nickel coating layer enables the carbon materials to avoid chemical erosion sequentially enhancing the stability of the composite and also endues the composite with improved properties, such as higher electrical conductivity, magnetism and good adhesion. There are many effective method to coat nickel on carbon nanomaterial , and one of them is the electroless plating method which has been wided employed for nickel coatings on many other materials. By using this method, some researcher have successfully obtained nickel coated carbon nanotube which is served as heterogeneous catalysis and medium for adhesion and transferring loads. Furthermore carbon fibres have also been coated with nickel, showing application in the field of capacitor, magnetism film, electromagnetic shielding film. Lately, it is reported that C₆₀ nano-whiskers can be coated with other kind of metal, silver by using spinning disc process. However, there has been no report on nickel coated C₆₀ nanorod to the best of our knowledge.In this work, we have successfully obtained nickel coated C₆₀ nanorod by using electroless plating method and studied their magnetic properties. After granulation sensitization and activation, C₆₀ nanorod was covered by nickel particles. The coating layer become continuous and compact with plating time increasing, and the coating layer mainly consists of Ni and P, the weight ratio of nickel and phosphorus is estimated as 1:0.09 approximately, so the composition of the coating layer thus can be indicated as Ni0.85 P0.15. The XRD of Ni from coating layer is accordant to nickel nanoparticals which were obtained from the same experiment ,they are both crystalline(fcc structure),We estimated the average size of nickel particles by using the Scherrer equation[17], it is about 5 nm. To further verify the structures of samples, we also carried out Raman spectroscopy and magnetic hysteresis. Compared with the Raman spectrum of C₆₀ nanorods in details, especially Ag2 mode at 1468.5 cm-1, there is no obvious change in the spectrum, suggesting that no change occurred in the structure of C₆₀ after coated by nickel. We can find the size of coating layer is very small from hysteresis loop and magnetic parameters, and the hysteresis loop shows a characteristic feature of super paramagnetic property.As a magnetic material, the nickel-coated C₆₀ nanorods are expected to have potential application, such as electromagnetic screen, radar absorbing materials and memory materials. The coated nanometer nickel particles are also expected to be served as catalyst in the high pressure studies, which may decrease the transformation condition from C₆₀ to superhard phases.Recently, the studies to polymerization of C₆₀ are all focus on bulk materials, in this work, we study the polymerization of C₆₀ nanorods by a method of high pressure and high temperature, and we will discuss the effect which nickel layer gave to polymerization. As a unique technology, high pressure affords a very powerful help to transform the structure of nanomaterials, it impacts some quality of nanomaterials directly. On the other hand, Because C₆₀ has the mixture of SP3and SP2, currently, it is considered can transform to superhard phase easily, in my dissertation , we carried out laser heating experiments to transform the structure of C₆₀ nanorods under high pressure.