Electrochemical Degradation of Refractory Pollutant Using a Novel Microstructured TiO2 Nanotubes/Sb-Doped SnO2 Electrode

A novel Sb-doped SnO2 electrode featuring high oxygen evolution potential, excellent electrocatalytic performance, and long stability toward electrochemical degradation of refractory organic pollutants was constructed by designing and regenerating the microstructure of the Ti substrate. Highly ordered TiO2 nanotubes (TiO2−NTs) with three-dimensional microstructure, large specific surface area and space utilization rate could be grown in situ on Ti substrate under controlled conditions, followed by being implanted with Sb-doped SnO2 through a surfactant-assisted, sol−gel method under vacuum environment. The amount of Sb-doped SnO2 and service lifetime for the constructed electrode (TiO2−NTs/SnO2) were 2.4 and 12 times as much as those for a traditional Sb-doped SnO2 (SnO2) electrode. Moreover, the constructed electrode performed at higher oxygen evolution potential and exhibited superior electrochemical capability to that on SnO2 electrode. Compared with low TOC removal by the SnO2 electrode, the TiO2−NTs/SnO2 electrode could completely mineralize benzoic acid (BA) under the same condition. The mineralization current efficiency and the first-order kinetic constant for BA degradation at the TiO2−NTs/SnO2 electrode were 1 and 3.5 times greater than those observed for the SnO2 electrode.