Porous carbon derived from Metal–organic framework (MOF) for capacitive deionization electrode

Highlights: • Porous carbons (PC) were obtained from the carbonization of MOF-5. • The PC-900 exhibited much higher electrochemical performance than AC. • The PCs derived from MOF-5 were investigated for CDI. • The maximum electrosorption capacity of 9.39 mg g⁻¹ was obtained by PC-900. - Abstract: Porous carbon (PC) was easily prepared by synthesis of a metal–organic framework (MOF-5) followed by carbonization step. The morphology, structure, Brunauer-Emmett-Teller (BET) surface areas, wettability, and electrochemical performance for PCs carbonized at different temperatures from 500 to 1000 °C were characterized by the techniques of scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), N₂ adsorption-desorption, contact angle of glycerin, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS), and compared with a commercially available activated carbon (AC). The results showed that MOF-5 was fully carbonated at 900 °C, having the highest specific surface area of 1563.09 m² g⁻¹ and the largest pore volume of 1.07 cm³ g⁻¹. The PC carbonized at 900 °C (PC-900) exhibited better wettability, a higher specific capacity and a lower charge transfer resistance than other PCs and AC. In further capacitive deionization (CDI) process, the PC-900 electrode exhibited 9.39 mg g⁻¹ CDI capacity, significantly higher than 5.47 mg g⁻¹ of AC electrode. More importantly, easy and good repeatability could be obtained for PC-900 electrode. This study suggests that the PC-900 derived from MOF-5 may be a potential electrode material for CDI