Preparation and characterization of Nd-Sb co-doped SnO2 nanoflower electrode by hydrothermal method for the degradation of norfloxacin

The unsatisfactory electrochemical activity and short service lifetime limited the wide application of Sb-doped SnO2 electrode. Here, Nd-Sb co-doped SnO2 nanoflower electrode on the Ti substrate was prepared by hydrothermal method. When the molar ratio of Nd:Sn was 7.5% in the precursor solution, the electrode has a small crystal size, large specific surface area, high oxygen evolution over-potential (2.18 V vs. SCE), low charge transfer resistance and strong ·OH generation ability. Hence, the Nd 7.5% electrode exhibited an excellent electrocatalytic activity with high chemical oxygen demand (COD) and total organic carbon (TOC) removal efficiency, and economic current efficiency for the degradation of norfloxacin (NOR). The effects of Nd doping content, Na2SO4 concentration, temperature, initial solution pH, initial NOR concentration and inorganic ions were also investigated. The degradation mechanism was explored by HPLC-MS and three degradation pathways were proposed. The toxicity of NOR and its intermediate products were evaluated by E. coli bacteria. Compared with Nd 0%, the lifetime of Nd 7.5% also prolonged about 3.5 times for the anti-corrosion ability of Nd. Thus, the Nd-Sb co-doped SnO2 nanoflower electrode with good electrooxidation activity and high stability provides a new strategy for the degradation of norfloxacin by electrochemical oxidation technology.