Synthesis of visible-light responsive graphene oxide/TiO₂ composites with p/n heterojunction

Graphene oxide/TiO₂ composites were prepared by using TiCl ₃ and graphene oxide as reactants. The concentration of graphene oxide in starting solution played an important role in photoelectronic and photocatalytic performance of graphene oxide/TiO₂ composites. Either a p-type or n-type semiconductor was formed by graphene oxide in graphene oxide/TiO₂ composites. These semiconductors could be excited by visible light with wavelengths longer than 510 nm and acted as sensitizer in graphene oxide/TiO₂ composites. Visible-light driven photocatalytic performance of graphene oxide/TiO₂ composites in degradation of methyl orange was also studied. Crystalline quality and chemical states of carbon elements from graphene oxide in graphene oxide/TiO₂ composites depended on the concentration of graphene oxide in the starting solution. This study shows a possible way to fabricate graphene oxide/semiconductor composites with different properties by using a tunable semiconductor conductivity type of graphene oxide.