Photoelectrochemical degradation of methyl orange by TiO₂ nanopore arrays electrode and its comparison with TiO₂ nanotube arrays electrode

Highly ordered TiO₂ nanopore arrays (TNPs) electrode was applied as an electrode material for photoelectrochemical (PEC) degradation of methylic orange (MO). As a comparison, the self-organized TiO₂ nanotube arrays (TNAs) electrode about 500 nm in length was fabricated by Ti anodization in 0.5 wt% HF-H₂O solution. The COD removal rate and color removal rate for PEC degradation of MO using the TNPs electrode was found to be 9 and 7%, respectively, as high as that obtained for TNAs electrode when biased at 0.5 V. The results indicate that the fast electron separation and transport properties of TNPs electrode makes it possesses enhanced PEC performance for the degradation of MO. In addition, the color removal rate of MO by TNPs PEC process increased with increasing bias potential and electrolyte concentration, but decreased with the increasing pH value and initial concentration of the reaction solution.