Two-dimensional bimetallic cobalt-copper metal organic framework for improved desalination performance of capacitive deionization

Abstract

Capacitive deionization (CDI) technology has recently attracted much attention due to its distinct advantages, which include energy efficiency, eco-friendly method, and simple process. Capacitive materials, such as activated carbon, carbon fiber, and carbon aerogel, have mostly been used. However, the conventional carbon-based materials still suffer limitations, such as low electrosorption capacity, slow desalination rate, and insufficient desalination capacity for high saline concentration. Herein, the 2 Dimensional-Cobalt-Copper sulfur linker-based MOF material was prepared by a solvothermal method to develop the performance of electrode material, namely 2D-CoCu sMOF. We applied the synthesized material with porous carbon material (AC) as an electrode material in the CDI desalination system. Owing to the fast and efficient electron transfer in the electrode layer and the lower interfacial resistance between electrode surface and saline electrolyte originating from the redox reactions of MOF structure, 2D − CoCu sMOF exhibited a much higher desalination performance, compared to the pristine AC. CDI experimental results showed that the salt adsorption capacity (SAC) of electrode using 2D − CoCu sMOF was significantly improved from 4.18 to 7.55 mg/g without any changes in the long-term stability test, which was over an 80% increase in desalination performance. This approach provides an effective and simple method for the preparation of MOF-based CDI electrode material, which could have potential for high-performance green technology including desalination applications.