Enhanced photoelectrocatalytic activity of Cr-doped TiO2 nanotubes modified with polyaniline

A facile method for preparation of Cr-doped TiO2 nanotubes (Cr-TiO2 NTs) modified with polyaniline (PAM) was developed. The obtained materials were analyzed with scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectroscopy. The photoelectrochemical property of PANI/Cr-TiO2 nanotubes was studied by voltammetry, photocurrent and electrochemical impedance spectroscopy (EIS). Using PANI/Cr-TiO2 NTs as photoanode, the removal of p-nitrophenol (PNP) by photoelectrocatalytic oxidation technique was investigated. Compared with Cr-TiO2 NTs, PANI/Cr-TiO2 NTs showed an increased efficiency in the photoelectrocatalytic degradation of PNP. Moreover, photoelectrocatalysis was more efficient for PNP degradation than electrochemical oxidation, direct photolysis, and photocatalysis. The influences of applied bias potential, initial concentration of PNP and solution pH on the photoelectrocatalytic degradation of PNP were investigated. Under optimized conditions, almost all PNP could be degraded on PANI/Cr-TiO2 NTs after 2-h photoelectrocatalytic treatment. (C) 2014 Elsevier Ltd. All rights reserved.