Solvothermal fabrication of three-dimensionally sphere-stacking Sb-SnO2 electrode based on TiO2 nanotube arrays

TiO2-NTs-based Sb-SnO2 electrode with three-dimensionally sphere-stacking structure was successfully fabricated by the solvothermal method, followed by annealing at 500 °C for 1 h. The physico-chemical properties of electrodes were characterized through scanning electron spectroscopy (SEM), X-ray diffraction (XRD) and electrochemical measurements. SEM result showed that TiO2-NTs/Sb-SnO2 electrode has morphology of vertically sphere-stacking coralline. Compared with Ti/Sb-SnO2, TiO2-NTs/Sb-SnO2 electrode has smaller grain size and greater specific surface area which can provide with more active sites. Compared with Ti/Sb-SnO2 electrode, TiO2-NTs/Sb-SnO2 has a higher oxygen evolution potential and stronger phenol oxidation peak, indicating an improved catalytic activity for phenol degradation. The kinetic analysis of electrochemical phenol degradation showed that the first-order kinetics rate constant on TiO2-NTs/Sb-SnO2 electrode is 1.33 times as much as that on Ti/Sb-SnO2, confirming that the sphere-stacking Sb-SnO2 based on TiO2 nanotube has a good electrocatalytic activity.