Composite Materials Based On Carbon, And Its Applications On Electrochemical Electrodes

As a new member of carbon materials, graphene has attracted considerable attention since its discovery in2004. The two-dimensional material exhibits many unique properties, such as high intrinsic electronic mobility at room temperature, high mechanical strength, large surface area, and thermal stability. These properties provide potential applications of graphene and graphene-based composites in many fields, such as nanoelectronics, sensors, batteries, and catalysis. Carbon nanotubes, which were considered as the basis of future nanoelectronic technology, have also attracted considerable attention. To obtain better performance, carbon nanotubes were modified with other materials and carbon nanotubes-based composites were synthesized by various methods.This study is mainly devoted to the synthesis and characterization of graphene, graphene-based composites and carbon nanotube-based composites.Graphene was synthesized by liquid-phase exfoliation method and chemical reduction method first, which was the basis of our next work. In this work, a new method——ultra-microtome method was proposed and has been proved that it can be used to obtain graphene nanoribbons.A self-assembly method was used to synthesize high-density nanoparticles on chemically reduced graphene. A mono-layer of1-pyrenemethylamine was self-assembled on the surface of graphene nanosheets via π-π stacking, which acted as the linker for high-density Pt nanoparticles. We also used pyrene derivative to synthesize high loading sample of other metal or semiconductor nanoparticles on graphene. A simple method was used to synthesize high-density ZnO nanoparticles on chemically reduced graphene.ZnO nanorods/graphene heterostructure was synthesized by hydrothermal growth of ZnO nanorods on chemically reduced graphene film. The hybrid structure was demonstrated as a biosensor, where direct electron transfer between glucose oxidase and electrode was observed. The charge transfer was attributed to the ZnO nanorod wiring between the redox center of glucose oxidase and electrode, as well as the ZnO/graphene heterostructure that facilitated transport of electrons on electrode. The research revealed that the band structure of electrode could affect the detection of direct electron transfer of glucose oxidase, which would be helpful for the design of the biosensor electrodes.At last, multishell nanotubes of polyaniline and carbon nanotubes were synthesized via a template approach. A thin layer of MnO2coated on carbon nanotubes acts as a reactive template for the consequent formation of the polyaniline coating. The polyaniline-carbon nanotubes show enhanced dispersibility in water and can be possibly used as a functional material of electrochemical capacitors with improved performance. The general method operates by coating carbon nanotubes on functional materials such as poly (3,4-ethylenedioxythiophene), polypyrrole, silica, and carbon.