Single-Charality Separation Of Single-walled Carbon Nanotubes And Synthesis Of Carbon Nanowires

One-dimensional carbon nanomaterials have attracted much attentions due to these unique structure and properties for several decade,which is more representative of carbon are single-walled carbon nanotubes,carbon atom chains,carbon nanowires.The contents of this thesis are based on the preparation and the characterization of these materials.Firstly,the background of the structure of the three kinds of one-dimensional carbon materials,the property characterization methods and the related research progress are provided in Chapter 1.Secondly,we present the research on ultrathin singlewalled carbon nanotubes prepared by hydrogen arc-discharge,and single chirality separation in Chapter 2.Thirdly,the liquid hydrogen electric arc method and end-substitution method to prepare and obtain high purity short carbon chain sample?C₈H₂?are discussed in Chapter 3.Finally,we present the preparation and characterization of C_2nH₂ filled single-walled carbon nanotube structure and carbon nanowires in Chapter 4.Main conclusions are as follows:1.High quantity,small diameter?<1.0 nm?and narrow diameter distribution of single-walled carbon nanotubes have been prepared by the hydrogen arc discharge.And,a suitable purification process also have been provided for such ultrathin carbon nanotubes.2.A temperature-pH controlled gel chromatography method have been developed to separate arc discharge single-walled carbon nanotubes sample,and five species semiconductor single-walled carbon nanotubes have been separated for the first time.By employing different wavelength Raman spectrum,we researched the different chirality single-walled carbon nanotubes on the dependence of the energy of the laser.The temperature-pH gel chromatography can provide a new way to solve the separation problem of high crystalline single-walled carbon nanotubes.3.The solid metal atom end carbon chains?Ag2C2n,n?8?can be synthesized at large scale through the end-substitution method.Ag₂C_2n as a kind of highly reactive intermediates can react with different end groups,and C_2nH₂ and C_2nI₂ have been prepared at high purity.Furthermore,the concentration of the obtained C₈H₂ was more than 50 times than previously reported.And,C₈H₂ can be selectively enriched from the purified C_2nH₂ solution through the ultrasonic cavitation and vacuum evaporation method.The Raman spectral characteristics of Ag₂C₂ n and high concentrated C_2nH₂ solution have been firstly studied in our experiment.We also found that Ag₂C_2n can selfdecompose at room temperature into 2³ nm silver nanoparticles and sp² structured amorphous carbon.4.Supercritical fluid method is more efficient than high temperature and pressure method for filling single-walled carbon nanotubes in solution.The characteristics Raman peaks of the composite structure of C_2nH₂ molecules filled single-walled carbon nanotubes was located at about 3620 cm-1.Furthermore,C_2nH₂ molecules encapsulated in single-walled carbon nanotubes can react with each other and transform to longer carbon chains within the confinement from single-walled carbon nanotubes by the high vacuum and high temperature treatment.