Hierarchical Porous Nitrogen-Doped Spray-Dried Graphene for High Performance Capacitive Deionization

Graphene foam materials have attracted particular attention for capacitive deionization (CDI) applications due to their robust conductive framework and open three-dimensional porous structures. However, their salt adsorption capacities (SACs) are limited by the bland macropores and poor compatibility with aqueous environments. Herein, hierarchical porous nitrogen-doped spray-dried graphene (N-SDG) is prepared through a spray-drying method followed by low-temperature nitrogen doping. The resulting material exhibits hierarchical porosity and a nitrogen-rich carbon framework which demonstrates an improved SAC of 19.6 mg g⁻¹ in 500 mg L⁻¹ NaCl solution, amongst the highest reported for graphene-based CDI materials. The method herein demonstrates a commercially attractive approach for the production of N-doped porous graphene material for CDI applications. These findings are expected to underpin new developments in low-cost graphene-based materials for a range of applications.