Abstract The sol-gel approach was utilized to make a copper-doped Ti/SnO 2 -Sb anode for electrochemical oxidation of norfloxacin (NOR). Sycanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD), linear scan voltammograms (LSV), and cyclic voltammetry (CV) were used to examine the anode’s surface morphology and electrochemical characteristics. The results show that the doped metal makes the anode coating denser and smoother, which is more conducive to resistance to electrochemical corrosion. The electrochemical degradation of NOR utilizing the constructed anode was examined in relation to reaction circumstances such as current density, pH value, and initial NOR concentration. Within the selected range of reaction conditions, the removal rate of NOR using Ti/SnO 2 –Sb–Cu electrode was significantly higher than that of blank electrode. The following were the shifting trends: NOR removal efficiencies grew with applied current density and initial NOR concentration, and reduced with increasing pH value. Water samples with different reaction times were taken and tested by UV-Vis spectrum. As can be seen from the results, with the progress of the reaction, the intensity of the characteristic peak decreased, indicating that NOR is degraded gradually. The electrochemical degradation pathways of NOR were studied using liquid chromatography coupled with mass spectrometry (LC-MS). Six intermediates were detected and a possible reaction pathway for the degradation of NOR by electrochemical oxidation was proposed.
Li Yang,Ma Hairun,Li Qianwei,Yan Guangxu,Guo Shaohui
Ti/SnO 2 -Sb electrodes possess high catalytic activity and efficiently degrade nitrobenzene (NB); however, their low service life limits their wide application. In this study, we used one-step hydrothermal synthesis to successfully prepare Pt-Nd co-doped Ti/SnO 2 -Sb nanosphere electrodes. Scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were applied to characterize the surface morphology, microstructure, and chemical composition of the electrodes, respectively. The electrochemical activity and stability of the electrodes were characterized via linear sweep and cyclic voltammetry, electrochemical impedance spectroscopy, and an accelerated service life test; their performance for NB degradation was also studied. An appropriate amount of Pt-Nd co-doping refined the average grain size of SnO 2 and formed a uniform and compact coating on the electrode surface. The oxygen evolution potential, total voltammetric charge, and electron transfer resistance of the Ti/SnO 2 -Sb-Nd-Pt electrodes were 1.88 V, 3.77 mC/cm 2 , and 11.50 Ω, respectively. Hydroxy radical was the main active radical species during the electrolytic degradation of nitrobenzene with Ti/SnO 2 -Sb-Nd-Pt. After Pt-Nd co-doping, the accelerated service life of the electrodes was extended from 8.0 min to 78.2 h (500 mA/cm 2 ); although the NB degradation rate decreased from 94.1 to 80.6%, the total amount of theoretical catalytic degradation of NB in the effective working time increased from 17.4 to 8754.1 mg/cm 2 . These findings reveal good application potential for the electrodes and provide a reference for developing efficient and stable electrode materials.