Synthesis of graphene platelets

Abstract

Graphene, a single-layer of graphite, is frequently termed a ‘wonder material’ due to the wide range of extraordinary properties it possesses and the potential it has for uses in a broad variety of different applications. Key to the realisation of graphene’s use in applications is the ability to produce large scale quantities of graphene with consistent quality, which remains a challenge to the field. The aim of this thesis was to investigate the synthesis of graphene via a number of different methodologies in order to develop novel techniques that are suitable to scale and that provide graphene materials that are useful in different applications. To this aim, four studies were carried out; two involving the ‘top-down’ synthesis of graphene from graphite and two involving the ‘bottom-up’ synthesis of graphene from molecular precursors. In the first study a series of intermediate materials between graphene oxide (GO) and reduced GO (rGO) were successfully produced using a well-controlled reduction reaction, and the trend in their properties was explored, while in the second study rGO was successfully produced using a novel method that is simple, scalable and environmentally friendly. In both these studies a novel method of handling GO was used that eliminated the requirement for the final, time consuming purification step of GO synthesis. In the third study bulk graphene platelets were successfully produced using a novel chemical vapour deposition (CVD) method, and in the final study the templated growth of graphene via CVD over metal microcrystals was investigated. The work builds on some relatively new concepts for graphene synthesis; including tailoring the graphene product to the particular application and size/shape control for bulk scale graphene platelets, and also presents an interesting case study on carbon growth on copper which may provide new insights into carbon synthesis in these systems.