Electrochemical degradation of dye on TiO2 nanotube array constructed anode

A high oxygen evolution potential (2.6V) and conductivity of Ti/TiO2 NTs/Ta2O5-PbO2 anode was fabricated by mixed metal oxide. A well-aligned TiO2 nanotubes was successfully prepared by using 1-butyl-3-methylimidazolium tetrafluoroborate as the electrolyte. The surface structure of anodes were characterized by scanning electron microscope, X-ray diffraction and energy dispersive X-ray spectroscopy. During the electrochemical degradation experiments, the effects of different anodes, current density, initial pH value and concentration were discussed. The results showed that co-doped Ta2O5 coating is an effective method to improve the surface morphology and the electrochemical characterization of Ti/TiO2 NTs/PbO2. At the initial pH value of 3 and current density of 12 mA cm(-2), the removal rates of Acid Orange 7 and total organic carbon with Ti/TiO2 NTs/Ta2O5-PbO2 anode were almost 100% and 98.3%. Comparing with Ti/PbO2 anode at the same charge consumption (3 A h L-1), the instantaneous current efficiency of the Ti/TiO2 NTs/Ta2O5-PbO2 anode and Ti/TiO2 NTs/PbO2 anode increased by 40.0% and 27.1%, respectively. The highest rate of k(center dot OH) on Ti/TiO2 NTs/Ta2O5-PbO2 anode was 12.4 mu mol (L min)(-1). The organic dyes are oxidized into CO2 and H2O by center dot OH radical. The reaction process and mechanism during the electrochemical degradation were discussed. (C) 2019 Published by Elsevier Ltd.