Reduced graphene oxide and activated carbon composites for capacitive deionization

Abstract

In this paper, reduced graphene oxide (RGO) and activated carbon (AC) composites (GAC) have been synthesized by a facile chemical method for the capacitive removal of salt ions from brackish water. The as-prepared composites have been characterized by scanning electron microscopy, N₂ adsorption–desorption and cyclic voltammetry. The GAC composite with 20 wt% graphene (GAC-20) exhibits the best electrochemical performance among all the samples, with a specific capacitance of 181 F g⁻¹. The electrosorption capacity of the GAC-20 electrode is found to be much higher than that of the AC electrode, indicating that RGO can serve as a flexible bridge to form a “plane-to-point” (RGO-to-AC) conducting network, which is beneficial for decreasing the aggregation of AC particles, and improves the electron transfer within the composite electrode. GAC composite should be a promising candidate as an electrode material for capacitive deionization (CDI) applications.