Enhanced visible light photocurrent response and photodegradation efficiency over TiO2-graphene nanocomposite pillared with tin porphyrin.

In this study, a nanostructure material of pillared graphene made of tin porphyrin functionalized graphene-TiO2 composite (TG) was successfully synthesized. The prepared compound showed high activity in the photodegradation reaction under irradiation of visible light. To investigate the effect of graphene as well as dye sensitization on the photoactivity of the catalysts, photocatalytic properties and photocurrent responses of the photocatalyst were examined. Results showed that the composite of graphene-TiO2 containing 3% graphene had the highest photoactivity. Besides, tin porphyrin-pillared TG composite (TGSP) material exhibited an excellent visible light photocatalytic performance in degradation of methyl orange dye. The photoelectrochemical investigations determined that compared with the pure TiO2 electrode, the TGSP electrode exhibited a 23-fold enhancement of photocurrent intensity, suggesting the synergistic effect of the TiO2, the graphene, and the tin porphyrin photosensitizer in these photocatalysts. Furthermore, the mechanism of the photocatalytic process of the synthesized catalysts and the charge transfer mechanism in the prepared TGSP via its band edge positions was also discussed.