High-performance capacitive deionization using nitrogen and phosphorus-doped three-dimensional graphene with tunable pore size

Capacitive deionization (CDI) is considered as a potential water purification technology for electrochemical removal of the salt from aqueous solutions. However, the development of an electrode material with adequate electro adsorption rate and capacity is still a major challenge. In this study, a N and P-doped three-dimensional (3D) structure of graphene with high conductivity and capacitance for high performance CDI was synthesized and possessed tunable pore size through phosphoric acid activation. It had a large specific surface area of 567.14 m2 g−1 due to the 3D hierarchical porous structure and highly crosslinked networks of graphene sheets. This novel material also had a high specific capacitance (177.19 F g−1). High specific capacitance and interaction of micropores with mesopores improved the desalination capacity up to 20.93 mg g−1. Consequently, the materials with high specific surface area, better specific capacitance and tunable pore size can have a great potential for efficient and practical desalination applications. [Display omitted] •High performance capacitive deionization with N-doped three-dimensional graphene electrode was achieved.•The electrode materials have high specific area, specific capacitance, and hierarchical pores structures.•Capacitive deionization performance possessed electrosorption capacity of 20.93 mg g−1 and maximum capacity of 30.92 mg g−1.