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

ABSTRACT

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.

KEYWORDS:

• TiO₂ nanotubes
• co-doping of cerium and manganese
• electrocatalytic oxidation
• decolourisation
• wastewater

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 21676146].