Nitrogen-rich mesoporous carbons derived from zeolitic imidazolate framework-8 for efficient capacitive deionization

Abstract In this study, novel nitrogen-rich mesoporous carbons (NKZCs) were synthesized with the zeolitic imidazolate framework-8 (ZIF-8) assisted with urea and KOH as the precursors for efficient capacitive deionization (CDI). The deionization tests showed that the NKZCs electrodes had an electrosorption capacity of 31.30 mg g−1 for 1000 mg L−1 NaCl solution at 1.2 V, higher than those of carbons obtained from the ZIF-8/KOH composite (20.29 mg g−1) and single ZIF-8 (17.18 mg g−1). Besides, there was no significant decrease of the electrosorption capacity after 50 adsorption-regeneration cycles, indicating the excellent recyclability of the NKZCs electrodes. The material and electrochemical measurements revealed that the enhanced CDI performance of the NKZCs electrodes was ascribed to the superior mesoporous structure and rich nitrogen content which not only facilitated the ion transportation but also improved the electrical conductivity and hydrophilicity of the NKZCs. In a conclusion, the NKZCs would be a promising material for application in the CDI.