Fabrication of Graphene via Catalytic Graphitisation of Solid Carbon Sources

Abstract

This work has suggested two feasible routes for both 2-dimensional (2D) and 3-dimensional (3D) graphene fabrications on the basis of catalytic graphitisation of solid carbon sources, with proposed mechanisms. Graphene growth with ferric chloride (FeCl3) and glucose (C6H12O6) was explored in aspects of uniform liquid layer formation, appropriate heat treatment methods and sufficient sample cleaning. The 2D graphene on silicon (Si) wafer, as well as foam-structured 3D graphene, were both obtained through straightforward heat treatment of FeCl3 and glucose mixture at a low temperature of 750 °C. The graphene produced was further characterised by its morphological and chemical properties. Crystal structure and structural information were also obtained with X-ray diffraction (XRD) and Raman spectroscopy. Graphene synthesised through this route has comparable defect density with typical graphene oxide (rGO) products. The defect formation mechanism was studied and proposed with regard to a possible excess of carbon source in the material. To avoid forming excessive graphene layers, FeCl3 was replaced by copper (Cu) particles in pursuit of self-limited growth. The solid carbon source was changed to Polyacrylonitrile (PAN) since it can be pre-oxidised to a more rigid form and protect 3D graphene foam from collapse by enhancing its structural strength and toughness. Interconnected 3D mesoporous graphene foam consisting of 7-8 graphene layers and a large specific surface area of 610 m2/g was successfully synthesised. X-ray photoelectron spectroscopy (XPS) results confirmed the transformation of sp3 C to sp2 C. The defects detected via Raman spectroscopy are believed to be related to the nano-sized domain observed in between graphene patches. A correspondent 3D graphene domain developing mechanism was proposed, which hopefully will give an insight into graphene growth on 3D Cu-system substrates.

Date of Award	31 Dec 2021
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Ping Xiao (Supervisor) & Jiashen Li (Supervisor)