A promising electrode material modified by Nb-doped TiO2 nanotubes for electrochemical degradation of AR 73.

A distinctive SnO2Sb electrode with highly ordered Nb doped TiO2 nanotubes sheet as a new substrate, obtained by NbTi alloy anodization, is prepared by pulse electrochemical deposition for the first time as electrocatalytic oxidation anode for wastewater treatment. The novel electrode has a larger surface area and smaller crystallite particles than conventional SnO2Sb electrodes as obtained from the analysis of scanning electron microscopy and X-ray diffraction. Compared with Ti/SnO2Sb and Ti/TiO2-NTs/SnO2Sb prepared by pulse electrochemical deposition, the electrode modified by NbTiO2-NTs has the higher oxygen evolution potential of 2.29 V (vs. Ag/AgCl), and the lower charge transfer resistance, which decreased by 65% and 79%. The service lifetime of NbTi/NbTiO2-NTs/SnO2Sb is 4.9 times longer than that of Ti/SnO2Sb and 1.9 times longer than that of Ti/TiO2-NTs/SnO2Sb. The new electrode is proved to have an excellent electrochemical oxidation and degradation ability using Acid Red 73 as a target organic pollutant. The AR 73 removal, chemical oxygen demand removal and kinetic rate constant are increased obviously due to the introduction of NbTiO2-NTs. Besides, the energy consumption reduces 37.2% and 31.4% in contrast with Ti/SnO2Sb and Ti/TiO2-NTs/SnO2Sb. Hence, the Ti/SnO2Sb modified by NbTiO2-NTs is a very promising anode material for the electrochemical treatment of dye wastewater.