Filled Carbon Nanotubes: Preparation, Characterization And Use In Electroanalysis

Owing to their remarkable electronic and mechanical properties, carbon nanotubes (CNTs) have received considerable attention in the communities of nanoscience and nanotechnology. CNTs also have a unique structure that encapsulates a one-dimensional volume of space, which serves as a constrained reaction chamber. This dissertation is primarily focused on the noncovalent modification of CNTs by filling with alien materials to create heterostructures while maintaining their integrity.By far, there are two basic strategies of filling: post-production methods or in-situ synthesis of filled CNTs. Chapter one gives review on both strategies followed by different filling processing in chapter two and chapter three.As for post-processing filling, CNTs must come first. The synthesis of few-walled CNTs (FWNTs) is explored by tuning the catalyst composition and carbon feeding rate. Raw CNTs are purified by soaking in HC1 solution, and then filled with fluorescent dyes via diffusion method in liquid media, followed by fluorometer measurement. Besides, for the first time, sulfur dioxide is served as an additive to promote the yield of FWNTs. Distinguished from CNTs, a series of other carbon nanostructures such as carbon capsule, filled CNT and coiled carbon are also obtained.Differing from the former filling strategy, in-situ method is a process in which filling of the lumen and CNTs' growth take place simultaneously. Based on the well understanding of in-situ filling mechanism, Fe filled CNTs are successfully made by utilizing FeCl₃ anhydrous as floating catalyst precursor though ferrocene was assumed to be a better one conventionally. The as-grown products are evaluated by ESEM, TEM, XRD, Raman, TG and VSM. The effects of the vaporizing temperature of catalyst precursor and the presence of hydrogen on the formation of filled CNTs are investigated in detail. Aligned CNT arrays are obtained in the absence of hydrogen.In addition, durable membranes made up of Fe-filled CNTs are prepared under optimized condition, and then serve as working electrodes in the bioanalysis. The response of the electrode in the presence of dopamine is studied by cyclic voltammetry.