Highly pore-expanded benzidine-functionalized graphene framework for enhanced capacitive deionization

Capacitive deionization (CDI) is a promising technology for water 0. The electrode material plays a vital role in electrosorption capacity. Its porous nanostructure can promote capacitive deionization performance. Here, a one-pot synthesis of p-phenylenediamine-or benzidine-(DAB) functionalized graphene (DAB-mGO) was achieved using graphene oxide (GO) as a precursor by simultaneous nucleophilic addition, an amide reaction and an electrostatic self-assembly technique. DAB-mGO exhibits a significantly increased conductivity, specific surface area and pore volume compared with GO, which indicates that it can be used as a CDI electrode material for desalination in brackish water. DAB-mGO(130) that was obtained at 130 degrees C exhibited electrosorption capacities of 7.88, 8.02 and 13.55 mg/g in Na+, Me+, Ca2+ solutions, respectively, at 1.4 V. These values are 1.3-1.5 times higher than commercial activated carbon. These observations indicate that the simple organic functionalization of GO is an effective approach to increase the CDI performance because of the generation of useful porous nanostructures. A rational combination of organic molecules and inorganic GO can be used to fabricate environmental and economical CDI electrode for application in CDI and energy storage.