Optimized Indium modified Ti/PbO2 anode for electrochemical degradation of antibiotic cefalexin in aqueous solutions

Abstract

In this study, the Indium doped Ti/PbO 2 electrode (marked as Ti/In-PbO 2 ) was prepared via simple electrodeposition technology for electrochemical degradation of cefalexin (CLX). To obtain the effect of Indium on the electrochemical activity and stability of Ti/PbO 2 electrode and optimize the doping amount of Indium, the morphology, crystal structure, element state, electrochemical activity and stability of Ti/In-PbO 2 electrodes with different Indium amounts were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), fluorescence spectroscopy, linear sweep voltammetry (LSV), cyclic voltammetry (CV), chronoamperometry (CA), electrochemical impedance spectroscopy (EIS) and Tafel curve. The results showed that when the InNO 3 concentration in electrodeposition solution was 15 mM/L, the Ti/In-PbO 2 electrode possessed the best electrocatalytic activity and the highest stability due to its denser structure, finer grains, larger specific surface area, and stronger ability to generate hydroxyl radicals. The electrochemical degradation rate constant of CLX at Ti/In-PbO 2 anode was 1.93 times faster than that at pristine Ti/PbO 2 electrode. Additionally, the influence of current density, initial pH, initial CLX concentration and electrolyte concentration on removal efficiency of CLX was investigated and the degradation pathway of CLX was proposed. • Doping indium greatly improved the electrochemical activity of PbO 2 anode. • Tafel curve was adopted to evaluate the stability of Ti/In-PbO 2 electrode. • Chronoamperometry was performed to explore electrochemical oxidation of cefalexin. • The electrochemical degradation mechanism of cefalexin was proposed.