Metal-organic framework-derived carbon/N-doped three-dimensional reduced graphene oxide composite with high capacitive deionization performance

Capacitive deionization (CDI) is an electrostatic adsorption water treatment technology based on capacitor structure and charge-discharge principle, which has the advantages of pollution free, low energy saving, and high value added. Herein, a novel metal-organic framework (MOF)-derived carbon (PC)/nitrogen-doped three-dimensional reduced graphene oxide composite was prepared for CDI elec-trode material. In this nanoarchitecture, PC was attached to the N-doped graphene sheet, formed a hi-erarchical porous structure, and provided more active sites and ion transfer channels, which featured with enhanced the salt adsorption capacity (SAC) and rate. The carbonized products (NHG/PC-70 0) showed a high nitrogen content of 10.78 at.% and large surface area (432.3 m2/g), which was conducive to improve electric conductivity. Accordingly, the specific capacitance of 370.9 F/g and excellent long charge-discharge cycling stability were obtained at 1 A/g current density. In CDI experiments, the NHG/ PC-70 0 electrodes displayed an outstanding SAC of 28.17 mg/g with an initial concentration NaCl solution of 500 mg/L, and the SAC was reduced 4.6% after six CDI regeneration cycles. It was found that the NHG/ PC-70 0 could be considered as a promising electrode material in the field of water treatment.(c) 2022 Elsevier Ltd. All rights reserved.