In situ synthesis of ultrathin 2-D TiO2 with high energy facets on graphene oxide for enhancing photocatalytic activity

Two kinds of TiO2 with novel structures, interpenetrating anatase TiO2 tablets (IP-TiO2), and overlapping anatase TiO2 nanosheets (OL-TiO2) with exposed {0 0 1} facets, are synthesized. The graphene oxide (GO) supported ultrathin TiO2 nanosheets (OL-TiO2/GO) is also prepared by one-pot hydrothermal method. The microscopic feature, morphology, phase, and nitrogen adsorption-desorption isotherms are characterized. The performance of photocatalytic degradation of methyl blue is also measured. Compared with IP-TiO2, the OL-TiO2 with GO possess higher photocatalytic efficiency. The GO can improve the photocatalytic property by increasing specific surface area, accelerating the separation of electron-hole pairs, as well as extending the electron life. The growth process of TiO2 nanosheets on graphene oxide layers probably follows a step-growth mechanism with F− as morphology controlling agent. The steps on the surface can improve the photocatalytic activity further due to the increase of dangling bonds of 5-coordinated Ti (Ti5c) which are considered to be the active sites in the photocatalytic reaction.