Graphene/SnO2 nanocomposite as an effective electrode material for saline water desalination using capacitive deionization

Abstract

Capacitive deionization (CDI) is a second generation electrosorption technique for removing the salt ions from the brackish water. Among the carbonaceous materials, graphene can be considered to be a promising CDI electrode material due to its exceptional physical properties and chemical tenability. In this study, graphene/tin dioxide nanoparticles composites (Gr/SnO2) with different proportions were successfully synthesized via microwave irradiation; their electrosorption performances in CDI unit were investigated. The morphology, crystal structure and electrochemical performance were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and cyclic voltammetry. The obtained results indicated that incorporation of SnO2 into graphene has a great impact for enhancing the electrosorption capacity. Compared to pristine graphene electrode, higher specific capacitance was observed for all the fabricated Gr/SnO2 composite electrodes. Specifically, the electrode having 15wt% SnO2 exhibits distinguished electrochemical performances: high specific capacitance (323F/g), excellent cycling stability, very good salt removal efficiency (83%), and distinct electrosorptive capacity of 1.49mg/g. Overall, the present study demonstrates an effective and facile route to distinctly improve the desalination performance of graphene-based electrodes for CDI technology.