Preparation and photoelectrochemical performance of expanded graphite/TiO2 composite

• EG/TiO2 composite was successfully synthesized by a modified sol-gel method.
• EG/TiO2 displayed high separation and transfer of the photoinduced electrons.
• EG/TiO2 photoelectrode exhibited excellent photoelectrocatalytic efficiency.
• The contribution of series of active species scavengers was investigated.
• The enhanced photoelectrocatalytic mechanism was proposed.

Expanded graphite/Titanium dioxide (EG/TiO2) 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/TiO2 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 TiO2 nanoparticles were dispersed uniformly on the surface and edges of EG sheets. Transient photo generated current and
• OH radicals given by EG/TiO2 photoanode was higher than that of TiO2 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 TiO2 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.

The chemical-coupling EG/TiO2 composite was successfully synthesized by a modified sol-gel method and then was fabricated as a photoelectrode through the hot-press approach. The EG/TiO2 photoelectrode exhibited high catalytic activity and stability, which was ascribed to EG as suitable electronic conductors to facilitate charge collection and charge transport.Figure optionsDownload as PowerPoint slide