Synthesis of TiO2/C composite material for capacitive deionization (CDI) technology

Abstract

Hybrid Capacity Deionization (HCDI), a water treatment method currently undergoing significant development, offers advantages in efficiency and the desalination speed. With its high specific surface area and excellent electrical conductivity, carbon-based materials such as graphene, activated carbon (AC), carbon nanotubes (CNTs) and their composite materials are being used as electrodes in the HCDI. This paper presented the synthesis of a composite of TiO2 and some carbon materials like graphene, carbon black (C65) and CN using the sol-gel method for HCDI electrodes. The results showed that the TiO2/C composite could store energy via both a double-layer capacitance and a pseudocapacitance mechanism, with a maximum specific capacitance of 101.7 F.g-1 when using TiO2/CNTs as the electrode in a 1 M Na2SO4 solution at a scan rate of 5 mV.s-1. The salt adsorption was investigated with a 200 ppm NaCl solution, and the specific adsorption capacity (SAC) and the average salt adsorption rate (ASAR) of this electrode at 1.2 V were 27.1 mg.g-1 and 7.10 mg.g-1.min-1, respectively. Based on these results, the TiO2/C composite material has potential for use as an electrode material in salt adsorption processes.