Fabrication of two dimensional nanostructure based on carbon materials and their applications

Abstract

The two dimensional (2D) nanostructure presents interesting charateristics such as a large flat surface area with atomic thickness caused by structural uniqueness and also has been investigated recently for applications into electronics, optoelectronics, and even electrochemical fileds. To data, the synthesis and application study of zero dimensional (0D, e.g., fullerene and quantum dots), one dimensional (1D, e.g., carbon nanotubes and nanowires), and three dimensional (3D, e.g., mesoporous materials and nanocubes) nanostructures has been well developed by many kinds of researchers due to their excellent properties. 2D nanostructure, on the other hand, has remained without noticeable progress until recent emergence of processes for producing graphene. A variety of 2D nanomaterials (e.g., h-boron nitride, molybdenum disulfide, and g-carbon nitride) are reilluminated and reinvestigated for the academic interesting and potential applications with a new era by graphene. Here, I introduces the synthesis and modification of 2D nanostructure based on carbon materials. Especially, 2D nanomaterials presenting in this work are graphene and graphitic carbon nitride. They have equivalent structural feature whereas their properties and applications are different. First of all, graphene was prepared by modified Hummers’ method from graphite. Graphene oxide, another 2D nanomaterial different from graphene, is the intermediate state in the process of graphite exfoliation through strong acid treatment and possesses various functional groups as a result of the oxidation. Finally, reduced graphene obtained by doping / reducing agent and heat treatment can be produced in large quantities. Furthermore, nitrogen doping (N-doping) reduced graphene films shows one of the lowest sheet resistance values ever reported from the reduction of graphene oxide films. Secondly, graphitic carbon nitride representing the property of semiconductor is successfully synthesized by heat treatment in chemical vapor deposition (CVD) chamber under nitrogen atmosphere. Moreover, metal seized graphitic carbon nitride of metal porphyrin-like structure is also synthesized with addition of multivalent metal ions. To verify this unusual moity in the carbon nitride network, many kinds of analytical tools and theoretical calculation based on density functional theory (DFT) are utilized. Finally, electrochemical property of metal-seized carbon nitride is investigated by cyclic voltammetry (CV) study.