Optimizing activated carbon electrodes and improving their electrochemical performance through nitrogen doping and HNO3 modification

Abstract

In order to optimize the process conditions, electrodes were prepared by mixing coal-based activated carbon (AC), polyvinylidene fluoride (PVDF), and conductive carbon black on a graphite plate. To enhance the adsorption capacity of the electrode, nitrogen-doped modification and nitric acid modification were sequentially performed on AC. Characterization methods included scanning electron microscopy (SEM), specific surface area (BET), x-ray photoelectron spectroscopy (XPS), and other analytical techniques. Contact angle and cyclic voltammetry tests were also conducted on the electrode. The experimental results showed that the modified material's specific surface area increased from 482.843 m2/g to 856.073 m2/g, the electrode's specific capacitance reached 404.56 F/g. For better utilization of AC for electrosorption, new nitrogen- and oxygen-containing functional groups were introduced to provide additional electrons, reduces the internal resistance of the material improves the electron mobility, and improves AC electrochemical performance. The removal of Cu2+ by modified AC reached 76.25 % at a Cu2+ concentration of 80 mg/L with an applied voltage of 1.5 V.