Functional Nano-materials: Electrochemical Synthesis, Characterization And Properties

Owing to their unique structures and excellent properties, nanomaterials, especially one-dimensional nanomaterials have various potential applications in nano-devices, photo-catalysis, lasers, sensing, batteries, superhy-drophobic surfaces. The properties of nanomaterials depend on their morphology and sizes. Therefore, it is important to develop new techniques for fabrication nanomaterials with desired structures. Electrochemical reaction can be accurately modulated by integrated charge passed through the electrochemical cell, and so the size and morphology of the product can be easily controlled. In this dissertation, several 1D nanomaterials were synthesized through template-free electrochemical routes. Furthermore, Three-dimensional materials built up of nanostructures were fabricated using galvanic cell corrosion method. The materials were well characterized and their potential applications were investigated.First, Cu(OH)2 nanoneedle and nanotube arrays were electrochemically synthesized by anodization of a copper foil in an aqueous solution of KOH without any template and additives. Cu(OH)2 nanoneedles can be successfully transformed to CuO nanoneedles with little morphology change by heating. Stable superhy-drophobic surfaces were successfully fabricated on abitary substrate by the combination of anodization and surface reaction technology. This technique has also been applied for the fabrication of copper wire with super-hydrophobic sub-microfiber coating to mimic water strider legs.Second, Large scale ZnO nanoneedles array were fabricated by anodization of a zinc foil in alkaline zincate ion solution at room temperature. Highly oriented ZnO nanoneedle/nanorods arrays have been fabricated by direct oxidation of zinc foil in alkaline zincate ion solution at near room temperature. The effect of temperature to the morphology was investigated. Furthermore, Ag2S nanowires were successfully fabricated by anodization of asilver foil covered by Ag2O. The influences of current density and the concentration of the aqueous electrolyte on the morphology of nanostructures were investigated.Third, poly(pyrenebutyric acid) has been synthesized for non-covalent sidewall functionalization of single-walled carbon nanotubes (SWNTs) by direct oxidation of a-pyrenebutyric acid in boron trifluoride diethyl etherate containing SWNTs. The initial feeding weight ratio of the monomer and SWNTs can strongly influence the thickness of the oligomer coating on SWNTs and also the diameter of the fibril nanocomposites. The composite can be stably dispersed in many common organic solvents and aqueous alkaline solutions. The structure and optical properties of PPBA and SWNT/PPBA composites have also been studied.3D dandelion-like porous nanostructures and 2D nanowalls of copper phosphate dihydrate built up of thin nanosheets have been synthesized simply by corrosion of a copper foil with aqueous phosphoric acid under mild conditions. Roughness surface were produced when the acid concentration was increased. The phosphate nanostructures can be converted into nanoporous CuO films by pyrolysis.