Trace cobalt, nitrogen co-doped graphene for high-performance membrane capacitive deionization

Porous graphene-based electrodes possess great potential in membrane capacitive deionization (MCDI) applications due to their high conductivity and specific capacitance. To further enhance their desalination performance, a MCDI system utilizing nanostructured porous graphene doped with trace amounts of Co and N atoms (CoNG) as the cathode, and N-doped graphene (NG) as the anode is proposed. The porous structure and co-doping of N and Co imparts CoNG with numerous active reaction sites and enhances its electrochemical stability. Besides, the combination of CoNG and NG electrode lowers the overall adsorption energy of the MCDI system. Under optimal conditions, a high desalination performance of 69.23 mg g −1 and a desalination rate of 2.307 mg g −1 min −1 have been achieved with an energy consumption of 0.36 Wh g −1 . This study highlights the potential of graphene-based materials in desalination and lays a foundation for further improvements in their desalination performance.