Cu@Cu2O/carbon for efficient desalination in capacitive deionization

Abstract

Electrode materials with strong desalting ability is an important research direction of capacitive deionization. In this study, HKUST-1 was successfully synthesized by the solvothermal method, and MOFs-derived porous carbon/Cu@Cu2O composites were prepared by simple pyrolysis as cathode materials for CDI. After high-temperature pyrolysis, the Cu+ site with unsaturated coordination is generated, and the structure changes from micropores to the coexistence of mesoporous and micropores. The complex pore structure is conducive to strengthening ion migration and diffusion. The results show that the porous carbon/Cu@Cu2O materials derived from MOFs depend on the pseudocapacitance behavior for capacitive deionization and desalination. At a voltage window of -1.2 V∼1.2 V, a current density of 40 mA/g, and 5 mmol/L NaCl, the HDC-1100 exhibited the best desalting capacity of 30.9 mg/g. HDC-1100 also has good cycle stability. After 20 cycles of adsorption and desorption, the desalting capacity almost does not decrease. Therefore, MOFs derived porous carbon/Cu@Cu2O composites are expected to be an excellent choice for CDI cathode materials.