Optimisation of a Ce-Mn co-doped SnO₂-Sb anode based on a nanotubular TiO₂ array for electrochemical decolourisation of wastewater

In this study, Ce and Mn co-doped SnO2-Sb electrode was prepared onto a Ti/TiO2 nanotubes surface. The nanostructure of the novel electrode was characterised by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS), and specific techniques were used to study the electrochemical characteristics of the electrode. SEM analysis results showed that TiO2 nanotubes could reduce the crack morphology and provide a larger surface area for loading the electrochemically active material. EDS analysis showed that Ce and Mn were doped into the electrode successfully. Under optimised conditions, the electrode prepared with Sn:Sb:Ce:Mn mole ratio of 100:10:3:3 has the best electrocatalytic performance. Ethylene glycol was used as the solvent in cerium-manganese co-doped Ti/TiO2-NTs/TiO2-SnO2-Sb electrode. Ce-Mn co-doped TiO2NTs/SnO2-Sb electrode has a high oxygen evolution potential of 1.79 V (vs. SCE) and a lower charge transfer resistance. The decolourisation extent of 30 mg L-1 methylene blue wastewater reaches 98.5% within 30 min. Finally, the main intermediates were identified by gas chromatography-mass spectrometer (GC-MS), and possible pathways for dye degradation were proposed. This study opens a door to the rapid electrochemical decoloursation treatment of wastewater by using an easily obtainable multi-metal co-doped electrode.