Issue 14, 2015

Band gap narrowing in nitrogen-doped La2Ti2O7 predicted by density-functional theory calculations

Abstract

In order to reveal the origin of enhanced photocatalytic activity of N-doped La2Ti2O7 in both the visible light and ultraviolet light regions, its electronic structure has been studied using spin-polarized conventional density functional theory (DFT) and the Heyd–Scuseria–Ernzerhof (HSE06) hybrid approach. The results show that the deep localized states are formed in the forbidden band when nitrogen solely substitutes for oxygen. Introducing the interstitial Ti atom into the N-doped La2Ti2O7 photocatalyst still causes the formation of a localized energy state. Two nitrogen substitutions co-exist stably with one oxygen vacancy, creating a continuum energy band just above the valence band maximum. The formation of a continuum band instead of mid-gap states can extend the light absorption to the visible light region without increasing the charge recombination, explaining the enhanced visible light performance without deteriorating the ultraviolet light photocatalytic activity.

Graphical abstract: Band gap narrowing in nitrogen-doped La2Ti2O7 predicted by density-functional theory calculations

Supplementary files

Article information

Article type
Paper
Submitted
11 Jan 2015
Accepted
23 Feb 2015
First published
25 Feb 2015
This article is Open Access
Creative Commons BY license

Phys. Chem. Chem. Phys., 2015,17, 8994-9000

Author version available

Band gap narrowing in nitrogen-doped La2Ti2O7 predicted by density-functional theory calculations

J. Zhang, W. Dang, Z. Ao, S. K. Cushing and N. Wu, Phys. Chem. Chem. Phys., 2015, 17, 8994 DOI: 10.1039/C5CP00157A

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