Three‐Dimensional N‐doped Porous Carbon Derived from Monosodium Glutamate for Capacitive Deionization and the Oxygen Reduction Reaction

Abstract Capacitive deionization (CDI) is a promising desalination technology and its development is highly dependent on the electrode materials. Here, a three‐dimensional N‐doped porous carbon (3D‐NPC) was fabricated for use as a CDI electrode material through the one‐step carbonization process with C 5 H 8 NO 4 Na as the carbon and nitrogen source and NaCl as a template. Benefiting from high‐level N doping (4.93 at %) and a high surface area of 1481 m 2 g −1 with an interconnected hierarchical porous structure propitious to the ion and electron transportation, the 3D‐NPC exhibited an excellent desalination capacity in CDI. It was also very impressive that 3D‐NPC was used as an electrode material for a Zn‐air battery, displaying outstanding catalytic performance with an open‐circuit voltage of 1.34 V. Furthermore, the Zn−air battery can drive the operation of a CDI device, showing a high salt adsorption capacity of 19.4 mg g −1 and good applicable stability. The findings in this work will pave a way to develop energy‐integrated capacitive deionization technology.