Degradation of tetracycline hydrochloride by electrocatalytic oxidation using NiO@Co3O4/Ti electrode

Tetracycline hydrochloride (TC-H) belongs to a class of broad-spectrum antibiotics and is difficult to remove from the environment, posing potential hazards to human health as well as the aquatic environment. In this paper, NiO@Co3O4/Ti, a dimensionally stable anode with NiO as the core and Co3O4 as the shell, was synthesized using a hydrothermal method. XRD, XPS, and SEM were conducted for characterization, revealing a constant charge transfer between Ni and Co, with mainly trivalent Co acting as the oxidant. The electrochemical characterization showed that the NiO@Co3O4/Ti electrode had a high oxygen evolution potential and low charge transfer resistance. Furthermore, 94.26 % of TC-H (100 mg/L) was degraded in 60 min under the optimal operating conditions (voltage of 10 V, 0.25 M NaCl, pH 7.88). According to radical quenching experiments, the active species O2− played an important role in the electrocatalytic oxidation process. In addition, the electrode maintained good stability after several degradation experiments.