In-process monitoring of graphene nanoplatelet production using Raman spectroscopy and NMR relaxation

As the range of applications of graphene related 2D materials (GR2Ms) widens, the production volumes of these materials are also increasing. To maintain confidence in the quality of the GR2M feedstock, industry requires in situ measurement methods that can be deployed easily in a production environment and provide reliable results quickly. In this paper, we demonstrate the potential of 1 H nuclear magnetic resonance (NMR) relaxation and Raman spectroscopy to address this need. 1 H NMR relaxation measurements performed at-line were able to provide results in under one minute, providing near real-time feedback for production monitoring. Alongside this, Raman spectroscopy was deployed in-line to enable obtaining real-time information from production, without the need to manually sample the material. By comparing the results against existing measurement methods, as well as laboratory-based Raman spectroscopy and 1 H NMR relaxation measurements, we demonstrate potential quality control approaches for GR2M production. In-process measurements of GNP production provide real-time information about material properties, enhancing process control.