Photocatalytic reduction synthesis of SrTiO3-graphene nanocomposites and their enhanced photocatalytic activity

SrTiO3-graphene nanocomposites were prepared via photocatalytic reduction of graphene oxide by UV light-irradiated SrTiO3 nanoparticles. Fourier transformed infrared spectroscopy analysis indicates that graphene oxide is reduced into graphene. Transmission electron microscope observation shows that SrTiO3 nanoparticles are well assembled onto graphene sheets. The photocatalytic activity of as-prepared SrTiO3-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 SrTiO3 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 (center dot OH) radicals were detected by the photoluminescence technique using terephthalic acid as a probe molecule and were found to be produced over the irradiated SrTiO3 nanoparticles and SrTiO3-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, center dot OH, h(+), and H2O2 are suggested to be the main active species in the photocatalytic degradation of AO7 by SrTiO3-graphene composites.