Hydrothermal Synthesis of rGO-TiO2 Composites as High-Performance UV Photocatalysts for Ethylparaben Degradation

A series of reduced graphene oxide-TiO(2)composites (rGO-TiO2) were prepared by hydrothermal treatment using graphite and titanium isopropoxide as raw materials. The structural, surface, electronic, and optical properties of the prepared composites were extensively characterized by N(2)adsorption, FTIR, XRD, XPS, Raman spectroscopy, and DRS. GO was found to be effectively reduced and TiO(2)to be in pure anatase phase in all composites obtained. Finally, experiments were performed to evaluate the effectiveness of these new materials as photocatalysts in the degradation of ethylparaben (EtP) by UV radiation. According to the band-gap energies obtained (ranging between 3.09 eV for 4% rGO-TiO(2)to 2.55 eV for 30% rGO-TiO2), the rGO-TiO(2)composites behave as semiconductor materials. The photocatalytic activity is highest with a rGO content of 7 wt % (7% rGO-TiO2), being higher than observed for pure TiO2(E-g= 3.20 eV) and achieving 98.6% EtP degradation after only 40 min of treatment. However, the degradation yield decreases with higher percentages of rGO. Comparison with rGO-P25 composites showed that a better photocatalytic performance in EtP degradation is obtained with synthesized TiO2(rGO-TiO2), probably due to the presence of the rutile phase (14.1 wt %) in commercial P25.