Graphitic-C(3)N(4)-hybridized TiO(2) nanosheets with reactive {001} facets to enhance the UV- and visible-light photocatalytic activity.

AnataseTiO(2)nanosheets with dominant {001} facets were hybridized with graphitic carbon nitride (g-C(3)N(4)) using a facile solvent evaporation method. On top of the superior photocatalytic performance of highly reactive {001} facets, the hybridization with g-C(3)N(4) is confirmed to further improve the reactivity through degrading a series of organic molecules under both UV- and visible-light irradiation. It is proposed that an effective charge separation between g-C(3)N(4) and TiO2 exists in the photocatalytic process, i.e., the transferring of photogenerated holes from the valence band (VB) of TiO(2) to the highest occupied molecular orbital (HOMO) of g-C(3)N(4), and the injecting of electrons from the lowest unoccupied molecular orbital (LUMO) of g-C(3)N(4) to the conduction band (CB) of TiO(2). Due to this synergistic effect, the enhancement of UV- and visible-light photoactivity over the hybrid is achieved. Furthermore, it has been revealed that holes were the main factor for the improved photoactivity under UV-light, while the OH radicals gained the predominance for degrading organic molecules under visible-light. Overall, this work would be significant for fabricating efficient UV-/visible-photocatalysts and providing deeper insight into the enhanced mechanisms of π-conjugated molecules hybridized semiconductors.

One-step preparation of graphene-supported anatase TiO2 with exposed {001} facets and mechanism of enhanced photocatalytic properties.

Anatase TiO2 nanosheets supported on reduced graphene oxide (RGO) were synthesized via a one-step, solvothermal method. During the solvothermal step, graphene oxide (GO) was reduced to RGO, and, subsequently, anatase TiO2 with 73.7% exposed {001} facets was grown in situ on the surfaces of the RGO nanosheets. Compared with pure TiO2, the RGO/TiO2 hybrid nanocomposite had improved photoactivity as a result of effective photoinduced electron transfer from TiO2 to the RGO acceptor through interfacial interactions. Trapping tests showed that the oxidation of dye molecules proceeded for about 22% through the reaction with (•)OH radicals, and the remaining 78% occurred via direct interactions with holes. The holes left in TiO2 crystals were the main reason for the enhanced photocatalytic properties of the RGO/TiO2 composite. This paper not only reports the fabrication of highly active photocatalysts but also gives deeper insight into the photocatalytic mechanism of carbon/TiO2 composites.

Synthesis of nano-sized anatase TiO2 with reactive {001} facets using lamellar protonated titanate as precursor.

Nano-sized anatase TiO(2) with exposed {001} facets was synthesized from lamellar protonated titanate precursor. Owing to small size (ca. 11 nm) and high surface area (155 m(2) g(-1)), the crystals with 26.1% {001} facets exhibited markedly superior photoactivity to reference ca. 76 nm anatase TiO(2) nanosheets with 88.4% {001} facets.