Details

Autor(en) / Beteiligte

• Tao, Junguang
• Yang, M
• Chai, J. W
• Pan, J. S
• Feng, Y. P
• Wang, S. J

Titel

Atomic N Modified Rutile TiO2(110) Surface Layer with Significant Visible Light Photoactivity

Ist Teil von

• Journal of physical chemistry. C, 2014-01, Vol.118 (2), p.994-1000

Ort / Verlag

American Chemical Society

Erscheinungsjahr

2014

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• It has been recently emphasized that the surface of a photocatalyst plays crucial roles on its photocatalytic performance. By nitridizing the top layer of the rutile TiO2(110) surface using reactive atomic N flux, we report direct experimental evidence of significantly enhanced photocatalytic activity under both ultraviolet (UV) and visible light irradiations. The visible light activity of a nitridized surface is found to be comparable to the UV light activity of the pristine surface. On the basis of X-ray photoemission spectroscopy (XPS) measurements and density-functional theory (DFT) calculations, top surface N doping efficiently narrows the local band gap, ∼2.0 eV, which accounts for the visible light activity. Under visible light excitation, nearly all free charges contribute to the photocatalytic reactions. The improvement of photocatalytic activity is attributed to the N 2p add-on shoulder at the valence band maximum (VBM) as well as the strong exchange-splitting at the surface that settles the N 2p z states inside the conduction band of the TiO2 matrix, which avails efficient charge transfer.