Effects of TiO2 nanotube array dimension and annealing temperature on the Acid Red 4 degradation in aqueous solution by photocatalytic process

摘要

Degradation of Acid Red 4 (AR4) by photocatalytic processes with TiO2 nanotube arrays (TNTs) ofnvarious dimensions was carried out in this study. TNTs was fabricated by the anodization ofntitanium foil in electrolyte containing fluoride. The dimension and the induced photocurrentnof TNTs were determined by a field-emission scanning electron microscopy and anpotentialstat/galvanostat, respectively. The well-defined and highly-ordered TNTs were formednat the anodization voltage ranging from 10 to 40 V in water/glycerol solution (20:80wt.%)ncontaining 0.5wt.% NH4F. TNTs annealed at 6008C was found to induce the highest photocurrentnand to exhibit the preeminent performance of AR4 degradation. The apparent first-orderednreaction rate constant for AR4 degradation was roughly linearly dependent on the inducednphotocurrent of TNTs, despite the dimension of nanotubes. The depths of incident UV lightnpenetration through the nanotubes and of AR4 diffusion inside nanotubes restricted thendegradation of AR4.