Hierarchical N-doped holey three-dimensional reduced graphene oxide with high performance capacitive deionization

Abstract

In this study, a novel three-dimensional reduced graphene oxide (NHGH-0.2) was synthesized via one-step hydrothermal treatment based on nitrogen doped and hydrogen peroxide etching. The preparation of NHGH-0.2 showed a hierarchical holey structure with high specific surface area of 874.9 m2/g, resulted from the synergistic effect of the N-doped and chemical etching. Electrochemical analysis showed ultrahigh specific capacitance of 303.1 F/g at a current density of 1 A/g and low charge transfer resistance, due to the excellent wettability and conductivity, which was help for rapidly diffuse and transfer of ions on the electrode surface. Capacitance was still maintained at 92.8% by the cycling stability test after 1000 charge–discharge cycles. The desalination performance applied for capacitive deionization (CDI) displayed the salt adsorption capacitive as high as 22.14 mg/g at the voltage of 1.6 V in the initial concentration of 500 mg/L NaCl solution. Therefore, the NHGH-0.2 electrode could be a promising CDI material for water treatment.