Nitrogen-doped functional graphene nanocomposites for capacitive deionization of NaCl aqueous solutions

Nitrogen-doped functional graphene nanocomposites (GO-MRF-x) for electrode materials in a capacitive deionization (CDI) application were conveniently prepared through a sol–gel polycondensation reaction catalyzed by Na 2 CO 3 under ambient pressure drying. The materials showed high surface functionalization (N and O groups) which were confirmed by X-ray photoelectron spectroscopy (XPS). The molar ratio of melamine with resorcinol had a marked effect on the specific surface area and porosity of the nanocomposites. The characterization results showed that with the specific surface area of 387 m 2  g −1 and N content of 7.26 wt%, laminated GO-MRF-0.8 material exhibited a good performance with high specific capacitance (222 F g −1 ), low charge-transfer resistance (0.10 Ω), and electrosorption capacity (16.72 mg g −1 ). Furthermore, the electrosorption isotherms were studied, and it was found that the ion electrosorption behavior of NaCl on GO-MRF-0 followed multilayer adsorption, whereas GO-MRF-0.8 exhibited a change from monolayer to multilayer.