Enhanced photoelectrocatalytic performance of TiO 2 nanotube array modified with WO 3 applied to the degradation of the endocrine disruptor propyl paraben

摘要

AbstractWe report on the photoelectrocatalytic degradation of the endocrine disruptor propyl paraben (PPB) using a TiO2nanotube (TiO2-NT) electrode preparedviachemical anodization, and a TiO2-NT electrode modified with WO3by electrodeposition. Solutions containing 50mgL?1PPB were subjected to the photoelectrocatalytic process in a 0.2L one-compartment electrochemical cell under UV/VIS irradiation, and the effects of bias potential (+0.5, +1.0 and +1.5V) and solution pH (3.0, 7.0 and 10) on the performances of the unmodified and modified electrodes were investigated. Scanning electron micrographs (SEM) showed that the nanotubes were highly organized and perpendicularly aligned with a mean length of 800nm. According to energy dispersive X-ray and SEM analyses, the concentration of W in the TiO2-NT/WO3electrode was ~0.75% and the distribution of the modifier was continuous and homogeneous on the surface, with pores uncovered and decorated with WO3. The photocurrent of the TiO2-NT/WO3electrode was improved by more than 20% in relation to its unmodified counterpart. The maximum degradation efficiencies were achieved at higher applied potentials and under acidic conditions for both electrodes. However, best results were obtained using the TiO2-NT/WO3electrode with an applied potential of +1.50V and at pH3. Under these conditions, more than 99% of PPB was removed in 30min and 94% mineralization was achieved in 60min. The photoactivity of the electrode was highly stable even after exhaustive application, indicating that WO3deposition is an important method for improving the properties of TiO2-NT electrodes as applied to organic oxidation.]]>