A first principles investigation of Bi2O3-modified TiO2 for visible light activated photocatalysis: the role of TiO2 crystal form and the Bi3+ stereochemical lone pair
Lucid, Aoife K.
Modification of TiO2 with metal oxide nanoclusters is a novel strategy for the design of new photocatalysts with visible light activity. This paper presents a first principles density functional theory (DFT) analysis of the effect of modifying TiO2 rutile (110) and anatase (101) and (001) surfaces with Bi2O3 nanoclusters on the band gap and the nature of the photoexcited state. We show that band gap modifications over unmodified TiO2 depend on the crystal form: modifying rutile (110) results in new Bi2O3 derived states that shift the valence band upwards. On anatase surfaces, there is little effect due to modification with Bi2O3 nanoclusters, but an enhanced UV activity would be expected. Analysis of electron and hole localisation in a model photoexcited state shows enhanced charge separation in Bi2O3-modified rutile (110) but not in Bi2O3-modified anatase. The effect of the Bi3+ lone-pair on the properties of Bi2O3-modified TiO2 contrasts with SnO-modified TiO2, consistent with the weaker lone pair in Bi2O3 compared with SnO.
Photocatalysis , TiO2 , Bi2O3 , Lone pair , Density functional theory , Energy gap
LUCID, A., IWASZUK, A. & NOLAN, M. 2014. A first principles investigation of Bi2O3-modified TiO2 for visible light Activated photocatalysis: The role of TiO2 crystal form and the Bi3+ stereochemical lone pair. Materials Science in Semiconductor Processing, 25, 59-67. DOI: http://dx.doi.org/10.1016/j.mssp.2014.01.005
Copyright © 2014 Elsevier Inc. All rights reserved. NOTICE: this is the author’s version of a work that was accepted for publication in Materials Science In Semiconductor Processing. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Materials Science In Semiconductor Processing [Volume 25, September 2014, Pages 59–67] http://dx.doi.org/10.1016/j.mssp.2014.01.005