Design of zinc oxide nanoparticles and graphene hydrogel co-incorporated activated carbon for efficient capacitive deionization

The development of high-performance electrode materials is the main factor in improving the efficiency of the capacitive deionization (CDI) process. Activated carbon is the most extensively used electrode material because of its excellent physicochemical properties and low cost; however, its desalination application has been largely limited owing to its poor wettability. In this study, we prepared a ZnO nanoparticle-incorporated activated carbon/graphene hydrogel composite via ultrasonication and freeze-drying, followed by a hydrothermal treatment. As the hydrophilicity, electrical conductivity, and electrosorptive capacity were improved owing to the presence of the graphene hydrogel and ZnO nanoparticles, the as-fabricated nanocomposite showed excellent specific capacitance (746.5F g-1 at 10 mV s-1), salt removal efficiency (83.65%), and electrosorptive capacity (9.95 mg g-1). Thus, the nanocomposite design devised in this study has potential in realizing the practical CDI applications of activated carbon.