Evaluation of bias potential enhanced photocatalytic degradation of 4-chlorophenol with TiO₂ nanotube fabricated by anodic oxidation method

TiO₂ nanotube was fabricated using anodic oxidation method. The samples were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET). The obtained TiO₂ nanotube exhibited increased photoelectrocatalytic (PEC) activities compared to TiO₂ film for 4-chlorophenol (4-CP) degradation in aqueous solution. Comparing with electrochemical process (EP), direct photolysis (DP) and photocatalytic (PC), a significant PEC synergetic effect was observed. The factors influencing the degradation of 4-CP by the PEC process including bias potential, pH, initial concentration of 4-CP, UV light intensity and electrolyte concentration were examined. The results revealed that the bias potential played an important role in the degradation of 4-CP and the most efficient degradation of 4-CP was achieved in highly acidic and alkaline medium. Initial concentration of 4-CP was also a significant factor affecting the degradation of 4-CP. Moreover, the degradation rate increased with both UV light intensity and electrolyte concentration increasing.