Photocatalytic reduction synthesis of SrTiO(3)-graphene nanocomposites and their enhanced photocatalytic activity

SrTiO(3)-graphene nanocomposites were prepared via photocatalytic reduction of graphene oxide by UV light-irradiated SrTiO(3) nanoparticles. Fourier transformed infrared spectroscopy analysis indicates that graphene oxide is reduced into graphene. Transmission electron microscope observation shows that SrTiO(3) nanoparticles are well assembled onto graphene sheets. The photocatalytic activity of as-prepared SrTiO(3)-graphene composites was evaluated by the degradation of acid orange 7 (AO7) under a 254-nm UV irradiation, revealing that the composites exhibit significantly enhanced photocatalytic activity compared to the bare SrTiO(3) nanoparticles. This can be explained by the fact that photogenerated electrons are captured by graphene, leading to an increased separation and availability of electrons and holes for the photocatalytic reaction. Hydroxyl (·OH) radicals were detected by the photoluminescence technique using terephthalic acid as a probe molecule and were found to be produced over the irradiated SrTiO(3) nanoparticles and SrTiO(3)-graphene composites; especially, an enhanced yield is observed for the latter. The influence of ethanol, KI, and N(2) on the photocatalytic efficiency was also investigated. Based on the experimental results, ·OH, h(+), and H(2)O(2) are suggested to be the main active species in the photocatalytic degradation of AO7 by SrTiO(3)-graphene composites. PACS: 61.46. + w; 78.67.Bf; 78.66.Sq