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

Anatase TiO₂ nanosheets with dominant {001} 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 {001} 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 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.