The effective role of reduced-graphene oxide in visible light photocatalytic activity of wide band gap SrTiO3 semiconductor

Strontium titanate (SrTiO3) with wide band gap, is only active under UV light irradiation and not under visible light. On the other hand, occupies about 3-5% of the solar spectrum falls in the UV range. Hence, modification of SrTiO3 is necessary to improvement of the photocatalytic activity of it. In this work, coupling of SrTiO3 (STO) on reduced Graphene Oxide (rGO) was studied for its enhanced photocatalytic activity under visible light irradiation. The enhanced activity can be partially attributed to the transfer of photoexcited electrons and holes in the STO/rGO semiconductor. Understanding the rGO/semiconductor interaction is of key importance for the design and synthesis of next generation photocatalytic materials for efficient photocatalytic activity and environmental clean-up applications. Hence, the separation mechanisms of photogenerated electrons and holes for STO/rGO semiconductor have been a research focus. Based on the experiment results, a possible mechanism of the photocatalysis over STO/rGO were investigated by photoluminescence technique (PL) and DRS analysis. Determining free radical ways in the presence of appropriate scavengers of oxidation to fit the experimental results was also further discussed. In this mechanism, the rGO acts as photosensitizer for wide band gap of STO semiconductor which can be photoexcited for generating electron and hole pairs.