HCl-activated porous nitrogen-doped carbon nanopolyhedras with abundant hierarchical pores for ultrafast desalination

Exploring an emerging carbon-based material with optimized structure and controlled porosity is of sig-nificance for further heightening the capacitive deionization (CDI) performance and solving the problem of emergency fresh water supply. Herein, a porous nitrogen-doped carbon nanopolyhedra with hierarchical pores prepared via using zeolite-type metal-organic framework (ZIF-8) as precursor is reported and used for CDI. In order to prepare the nanomaterials with abundant hierarchical pore structure, the synthetic route of carbonization followed by HCl-activation is adopted. The resulting nitrogen-doped carbon mate-rials exhibit a bimodal porosity containing micro-and meso-pores, high specific surface area, and numer-ous exposed adsorption active sites. The excellent performance in structure ensures the ultrahigh desalination capacity of 37.52 mg g-1 and excellent recyclability (retained 90% over 30 cycles) of the as-prepared carbon electrode material. Notably, the above electrode demonstrates ultrafast desalination rate of 16.01 mg g-1 min-1, which is 2-8 times faster than the conventional carbon materials. This present work may provide a new insight for developing efficient MOF-derived CDI electrode materials and realiz-ing rapid water resource supply in emergencies such as outdoor survival or unexpected natural disasters.(c) 2022 Elsevier Inc. All rights reserved.

Automated summary

This study reports a new carbon-based material, a porous nitrogen-doped carbon nanopolyhedra, for enhanced capacitive deionization (CDI) performance. The material exhibits abundant hierarchical pore structure, high specific surface area, and numerous exposed adsorption active sites, leading to excellent desalination capacity, cycling stability, and significantly faster desalination rate compared to conventional carbon materials.