Exfoliated graphite/titanium dioxide for enhanced photoelectrochemical degradation of methylene blue dye under simulated visible light irradiation

Abstract

This work investigates the synthesis and application of nanocomposite electrode consisting of exfoliated graphite (EG) and titanium dioxide (TiO2) (EG/TiO2) for the photoelectrochemical degradation of organic pollutants in water. The EG/TiO2 composite electrode was prepared using Dendrimer as a binder and characterized with transmission electron microscopy, ultraviolet–visible diffuse reflectance, Brunauer-Emmett-Teller surface area analysis, scanning electron microscopy, energy dispersive spectroscopy, thermal gravimetric analyzer, X-ray diffractometry and X-ray photoelectron spectroscopy. XRD and Raman patterns of both the pure TiO2 and EG-TiO2 revealed Anatase phase of TiO2. The EG/TiO2 composite absorbed a noticeable amount of light in the entire visible light region compared to pure TiO2. The surface area and pore volume of pure TiO2 were observed to decrease after modification with the EG as a result of the interpenetration of the porous matrix of EG by the TiO2 nanoparticles. The EG/TiO2 photoanode was applied in the photoelectrochemical degradation of 0.1×10−4M methylene blue dye in 0.1M Na2SO4 under visible light irradiation. The photoelectrochemical degradation process resulted in enhanced degradation efficiency of 85% within 240min and was observed to be higher than that of photolysis and electrochemical oxidation processes.