Size separation of graphene oxide via multi-layer filtering by silica gel column

Abstract

The properties and applications of graphene-based materials largely depend on the lateral size and size distribution of graphene and its derivatives sheets. In this work, a novel size separation method was developed for graphene oxide (GO) sheets using a multi-layer filtering of silica gel column. GO sheets were separated into three groups with narrowed size distributions after filtering from the multi-scale holes that were formed due to the packing of irregular silica gel particles. This economical and continuous-operational separation method shows promising future to realize the size separation in industrial sector. The size separation mechanism was considered that the size of GO sheets affected the flow speed, owing to the friction force between the GO sheet and silica gel particle surface. In addition, the related reduced graphene oxide (rGO) was obtained via the separated GO. The size impact of rGO sheets on the electrochemical properties were studied using cyclic voltammetry (CV), galvanostat charge/discharge (GC/D) and electrochemical impedance spectroscopy (EIS).