Synthesis of nitrogen-doped carbon nanoboxes with pore structure derived from zeolite and their excellent performance in capacitive deionization

Abstract

Being regarded as one of the most promising desalination technologies, capacitive deionization (CDI) has attracted wide attention due to its low energy consumption, high salt removal efficiency, low cost and non-secondary pollution. However, fabricating electrode materials with low cost but highly efficient CDI performance still remains a huge challenge. Here in this work, we successfully synthesized nitrogen-doped porous hollow carbon nanoboxes (HCNBs) with controllable shell thickness and abundant hierarchical meso- and micropores. Besides Zeolite Socony Mobil-5 (ZSM-5) template-derived micropores, mesopores were newly developed by in situ polymerization of aminophenol and formaldehyde and subsequent carbonization. The prepared HCNBs samples displayed high specific surface area and pore volume, along with impressive electrochemical performances of 192.82 F g⁻¹ at a current density of 1 A g⁻¹. Further, the existing form of uniformly doped nitrogen in the carbon skeleton of HCNBs could be modified by heat treatment so that the conductivity and surface properties could be tailored to improve their capacitive performance and electrochemical stability. Accordingly, HCNB-based electrodes exhibited high deionization capacity of 32.3 mg g⁻¹ at 1.4 V in 500 mg per L NaCl solution as well as high salt removal retention ability up to 95.40% after 50 cycles, suggesting their promising applications in electrochemical desalination in the future.