Fabrication of Ti/TiO2/SnO2-Sb-Cu electrode for enhancing electrochemical degradation of ceftazidime in aqueous solution

Ti/SnO2-Sb electrode was widely used in wastewater treatment due to its less toxic and high oxidation activity. Unfortunately, it also exhibited shortcomings such as high energy consumption and instability. Herein, Cu doping TiO2/SnO2-Sb electrode was prepared by sol-gel and anodic oxidation. The addition of TiO2 could reduce the internal passivation of the electrode and the charge transfer resistance (R-ct) from 158 Omega to 86.42 Omega, reinforce its stability and oxidation efficiency. Cu was used to limit the growth of crack morphology and provide more effective active sites which increasing the adsorbed oxygen from 49.67% to 55.00%. They accelerated electronic transfer and reduced the surface potential of SnO2 respectively, improve the oxygen evolution potential (OEP) from 2.0 V to 2.7 V and increase the response current peak from 25.86 mA to 48.66 mA, which enhanced the oxidative degradation ability of the electrode. The degradation efficiency of ceftazidime by Ti/TiO2/SnO2-Sb-Cu was 97.65% and 81.87% after 20 consecutive cycles of use, which was much higher than 51.58% of Ti/SnO2-Sb. The experiment also optimized parameters such as current density, supporting electrolyte concentration, electrode spacing and pH. Finally, the possible degradation pathways and intermediates of ceftazidime were inferred by LC-MS.