Interfacial charge transfer and enhanced photocatalytic mechanisms for the hybrid graphene/anatase TiO<inf>2</inf>(001) nanocomposites

Key Words:Graphene;Charge transfer - Electrons - Energy gap - Nanocomposites - Solids - Titanium dioxide;Experimental observation - First principle calculations - Interfacial charge transfer - Interfacial electron transfer - Photocatalytic efficiency - Photocatalytic performance - Semiconductor photocatalyst - Visible-light irradiation
Abstract:In this paper, first-principle calculations based on density functional theory were carried out to explore the interface properties of the hybrid graphene/anatase TiO<inf>2</inf> (001) nanocomposites (G/AT(001)N). The effect of graphene hybridization on energy gap, surface chemical bonding, interfacial charge transfer, and visible light response was investigated in detail. Because of the hybridization of graphene, the band structure of the G/AT(001)N was modified, and the energy gap was reduced to 0.47 eV. Electrons in the bottom of the valence band (VB) of anatase TiO<inf>2</inf> could disperse to the upper part of the VB. And electrons in the upper part of the VB of anatase TiO <inf>2</inf> were likely to be directly excited to graphene under visible light irradiation, which promoted the formation of well-separated electron-hole pairs. The interfacial electron transfer in the ground electronic state promoted electrons increased on graphene and substantial holes accumulated in TiO <inf>2</inf>(001) facet. Good linkage between TiO<inf>2</inf>(001) facet and graphene could facilitate the charge transfer, promoting photocatalytic efficiency improvement. Hybridization of graphene brought an obvious red shift in the absorption edge and enhanced absorption intensity in the visible region, which indicated the enhancement of photocatalytic performance. The calculation results illustrated the reported experimental observation [J. Phys. Chem. Lett. 2011, 2, 894-899] and would provide new insights into the design of graphene-based semiconductor photocatalysts. © 2013 American Chemical Society.
Volume:117
Issue:31
Translation or Not:no

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