Surface effect on electronic and optical properties of Bi2Ti2O7 nanowires for visible light photocatalysis

We theoretically performed the structural, electronic, and optical properties of the pyrochlore Bi2Ti2O7 nanowires for photocatalytic applications using pseudopotential density-functional theory calculations. The groundwork of electronic structure calculations showed a possible band gap modification of the Bi2Ti2O7 nanowires compared to that of the bulk. The midband states induced by the oxygen atoms and bismuth atoms on the surface of nanowires leads to a shift in the valence band toward the conduction band, which enables reduction of the band gap. The calculated optical results indicated that the absorption edges shift of nanowires towards the red-light region. These theoretical results suggested that the pyrochlore Bi2Ti2O7 nanowires can be expected to be a promising candidate for photocatalytic applications such as solar-assisted water splitting reactions. VC 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4729553]