Synthesis and applications of novel graphene-based composites

• Main Author: Cao, Xiehong
• Other Authors: Zhang Hua
• Format: Theses and Dissertations
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/51163
• Institution: Nanyang Technological University

Graphene, a novel two-dimensional (2D) carbon material, has drawn intensive interest because of its distinct structure and excellent properties. Graphene-based composites are also highly promising in various fields such as electronics, sensors, energy storage, solar cells, and etc. Therefore, the mass production of high-quality graphene and the efficient synthesis of graphene-based composites with controlled morphology and properties are desirable to fulfill the requirements in a broad range of fundamental research and practical applications. To realize these aims, the following researches have been conducted. First, reduced graphene oxide (rGO)/carbon nanotube (CNT) composite (rGO/CNT) has been synthesized by a facile alcohol-CVD approach. This method used GO-coated SiO2/Si wafer as the substrate, cobalt nanoparticles as the catalyst and ethanol as the carbon source. Moreover, relying on dip-pen nanolithography (DPN) technique, catalyst precursor patterns were simultaneously deposited on the substrates of GO and SiO2, which were further used to study the affects of substrate on the growth of CNTs. Second, a convenient CVD method has been developed to synthesis of the novel composite of rGO and carbon nanowires (CNWs), i.e. rGO/CNW. The CVD process involved only one simple step, i.e. anneal of catalyst-coated GO substrate within CVD chamber. No external carbon sources like hydrocarbons or ethanol were required. In this method, GO sheet was served as the both template and carbon source for the synthesis of rGO/CNW composite. Based on this finding, parallel-aligned patterns of rGO/CNW composite can be obtained by pre-patterning of the GO sheets on SiO2/Si wafer, which was further used as chemical sensor. In addition, the diameter of CNWs can be controlled by tuning the annealing temperature. This work demonstrated that the synthesis of graphene-based composite via CVD approach could be achieved by using GO, the two-dimensional carbonaceous material, as the only carbon source.