Synthesis and characterization of TiO2 nanotube photoanode and its application in photoelectrocatalytic degradation of model environmental pharmaceuticals

BACKGROUND In this study, highly ordered titanium dioxide (TiO2) nanotube arrays with tunable inner‐diameter and morphology were synthesized by an anodizing method from titanium (Ti) foil by optimizing different preparation parameters, and acyclovir was degraded to test the photoelectrocatalytic activity of prepared nanotubes in a thin layer reactor. RESULTS The results indicated that anodization time, the concentrations of NH4F and HAc had significant effect on the surface morphology and inner‐diameter of TiO2 nanotubes. Various morphologies including honeycomb films and nanotube arrays were obtained under given conditions. Photoelectrocatalysis showed higher degradation efficiency than that of photocatalysis or electrolysis due to TiO2 nanotubes regular nanotubular effectively reducing the recombination of photo‐generated electron–hole pairs. The photoelectrochemical responses and degradation efficiencies of acyclovir were well related to the TiO2 crystallinity and morphology of TiO2 nanotube photoanodes. Regular nanotube array photoanodes displayed better crystallinity, higher photoelectrochemical response and higher photoelectrocatalytic activity than those of nanopore photoanodes. The best TiO2 nanotube photoanode was prepared at 30 V for 24 h in the ethylene glycol solution containing 0.20 mol L−1 NH4F and 0.50 mol L−1 HAc. CONCLUSION TiO2 nanotube photoelectrocatalysis technology is an effective way to decontaminate organic contaminants in water.