Capacitive deionization with nitrogen-doped highly ordered mesoporous carbon electrodes

Abstract

As a promising desalination method, capacitive deionization (CDI) is capable of addressing the issues of water resource shortage and water environment pollution. However, the electrode materials with high electrochemical conductivity and salt adsorption capacity are very important for CDI applications. Herein, nitrogen-doped highly ordered mesoporous carbon (NOMC) samples with mesochannels were synthesized by a self-assembly method and adopted as the CDI electrode material with a remarkable electrosorption capacity of 26.2 mg/g (significantly higher than those of nitrogen-doped carbon electrodes reported in the literature) and an excellent regeneration performance after consecutive electrosorption-desorption cycles. The structural and electrochemical properties of NOMC were fully analyzed that NOMC showed a hierarchically porous structure with a large number of mesochannels and demonstrated a significant improvement of hydrophilicity and electrochemical conductivity. The superior desalination performance of the NOMC electrodes was mainly owing to the enhanced pseudocapacitance induced after nitrogen doping with the capacitive contribution of 82.13% including the pseudocapacitance and the diffusion-controlled contribution of 17.87%.