GO Mediated TiO2 Nanotube Electrode for the Photoelectrocatalytic Degradation of Pentachlorophenol

Abstract

GO/TiO2 nanotube array electrode was prepared on a titania plate by a simple in-situ anodization method. The physicochemical characteristics of synthesized TiO2 and GO/TiO2 electrodes were determined by Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Raman Spectroscopy, Ultraviolet-vis diffuse reflectance spectroscopy (UV-vis DRS), Fourier Transform Infrared spectra (FTIR), Photoluminescence (PL) spectroscopy and X-ray photoelectron spectroscopy (XPS). Synthesized GO/TiO2 nanotube electrodes were adjudged for its efficacy in the photoelectrocatalytic (PEC) degradation of Pentachlorophenol (PCP) aqueous solution. Box-Behnken design (BBD) was used to optimize the effect of graphene oxide (GO) loading (0.005–0.25 g/L), pH (3–8), applied current (20–60 mA) and degradation time (10–120 min) on the decomposition of PCP and energy consumption. At optimum conditions, 91% degradation and 85% mineralization of PCP was achieved after 90 min under UV-A illumination with 0.015 g/L of GO concentration, 20.68 mA applied current and at pH 3.14 by consuming 0.00068 kWh energy. Effect of reactive species scavengers on the degradation of PCP has been studied and hydroxyl radical was determined. Based on the LC-MS analysis results possible intermediates were identified and corresponding decomposition pathway of PCP was proposed.