Pulsed discharge plasma for graphite exfoliation in liquid nitrogen

TL;DR

This study demonstrates a pulsed discharge plasma method in liquid nitrogen to exfoliate graphite, producing few-layer graphene, and investigates the underlying mechanisms through surface and particle analysis.

Contribution

It introduces a novel plasma-based technique for graphite exfoliation in liquid nitrogen and explores the mechanisms involved, including defect formation and plasma interactions.

Findings

Successful exfoliation of few-layer graphene achieved.

Surface defects and particle characteristics analyzed via TEM and SEM.

Modified experimental parameters reduced non-exfoliating defects.

Abstract

Highly Oriented Pyrolytic Graphite was exfoliated via pulsed discharge plasma in liquid nitrogen. The potential mechanisms involved were investigated by observing the treated surface of the graphitic material and the obtained particles. Non-exfoliating defects from the plasma treatment were observed and experimental parameter were modified to counteract those. One experiment was performed without exposing the HOPG directly to the discharges so as to better understand the plasma role. The exfoliated particles were observed via TEM and SEM to evaluate the defects, the size, the purity and the crystallinity but no quantitative characterization of their thickness was possible so the actual number of layer of each particle is unknown. Nonetheless, few layers graphene (FLG) was successfully exfoliated through this process. The proposed mechanisms were extrapolated from the observation of the damaged HOPG surface and the obtained particles but the correlation found does not prove causation.