Synthesis of Visible-Light Responsive Graphene Oxide/TiO2 Composites with p/n Heterojunction

Graphene oxide/TiO2 composites were prepared by using TiCl3 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.