Graphitic-C3N4-hybridized TiO2 nanosheets with reactive {001} facets to enhance the UV- and visible-light photocatalytic activity

Anatase TiO2 nanosheets with dominant {0 0 1} facets were hybridized with graphitic carbon nitride (g-C3N4) using a facile solvent evaporation method. On top of the superior photocatalytic performance of highly reactive {0 0 1} facets, the hybridization with g-C3N4 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-C3N4 and TiO2 exists in the photocatalytic process, i.e., the transferring of photogenerated holes from the valence band (VB) of TiO2 to the highest occupied molecular orbital (HOMO) of g-C3N4, and the injecting of electrons from the lowest unoccupied molecular orbital (LUMO) of g-C3N4 to the conduction band (CB) of TiO2. 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)-O-center dot 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 pi-conjugated molecules hybridized semiconductors. (C) 2014 Elsevier B.V. All rights reserved.