Graphene is known as the world’s thinnest material due to its 2-D structure, in which each sheet is only one carbon atom thick, allowing each atom to engage in a chemical reaction from two sides. Graphene flakes can have a very large proportion of edge atoms, all of which have a particular chemical reactivity. In addition, chemically active voids created by missing atoms are a surface defect of graphene sheets. These structural defects and edges play a vital role in carbon chemistry and physics, as they alter the chemical reactivity of graphene. In fact, chemical reactions have repeatedly been shown to be favoured at these defect sites.