Production and Characterisation of Porous Carbon Nanomaterials

Abstract

Three dimensional porous structures of graphene and carbon nanomaterials have many exciting uses in energy storage, as catalyst supports and for water treatment to name a few; thanks to their high surface area, record conductivity, stability and potentially abundant feedstocks. However, recent publications have highlighted the need for a greater understanding of these materials’ formation and characterisation methods if they are to be optimised for these applications.
Many graphene production methods result in a polydisperse mixture of flake sizes, thickness and chemical environment and understanding this complex distribution is important for many applications. Raman spectroscopy is a versatile method of graphene analysis but single point spectra cannot resolve this distribution and, in many cases, may misrepresent a material. By recording multiple spectra a statistical dataset is produced but the size required remains an important consideration. Herein a protocol was developed, utilising the convergence of data sets and a Monte Carlo based statistical method, to investigate the size of data set required for accurate characterisation. This was successfully applied to a range of carbon nanomaterials revealing different materials require bespoke analyses for complete characterisation, and even routine analysis can require hundreds of points.
This characterisation was then applied to graphitic carbon produced from metal catalysed graphitization; whilst many studies have probed the effect of different process conditions, carbon sources and metals, here we investigate the role of different salts of the same metal, previously considered irrelevant to graphitization. By analysing the distribution of material produced from three different cobalt salts: , and ; it was found the thermal stability of the metal source used is key to controlling the size of metal particle formed and thereby the pore structure and carbon produced. Such control can potentially be used to tailor the properties of carbon foams produced from low cost feedstocks.