Preparation and photoelectrochemical performance of expanded graphite/TiO2 composite

Abstract Expanded graphite/Titanium dioxide (EG/TiO 2 ) composite was synthesized via a modified sol-gel method. Scanning electrons microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and fourier transform infrared (FTIR) were employed for the characterization of the composites. The performance of the EG/TiO 2 photoanode was investigated through UV-visible diffuse reflectance spectrum (DRS), electro-chemical impedance spectroscopy (EIS) and photocurrent response (PCR). Photoelectrocatalytic (PEC) activities were evaluated by the yield of •OH radicals and degradation of phenol. And the enhanced PEC mechanism was proposed. The results showed that the anatase phase of TiO 2 nanoparticles were dispersed uniformly on the surface and edges of EG sheets. Transient photo generated current and •OH radicals given by EG/TiO 2 photoanode was higher than that of TiO 2 photoanode. When external potential (+2.0 V) was applied, the pH of the solution was set at 7, 96.3% of the added phenol (25 mg·L −1 ) was degraded within 90 min, which was much higher than the 29% removal seen on TiO 2 photoanode. The higher PEC performance could be ascribed to the highly conductive property of EG and higher separation and transfer efficiency of photoinduced charge carriers.