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Title: Ab-initio study of hydrogen doping and oxygen vacancy at anatase TiO{sub 2} surface

Density functional–pseudopotential calculations were performed to study the effects of hydrogen doping and oxygen vacancy, both individually and together, on the electronic structure and stability of (001) surface of TiO{sub 2} in the anatase phase. Based on our calculations, O/Ti termination is the most stable one, and it appears that p-states of deep and surface O atoms and d-orbitals of surface Ti atoms have roles in the valence band and, the conduction band comes from the d-orbitals of deep Ti atoms. Although, no considerable change was seen during H doping, a mid-gap state appeared below the conduction band in the O vacancy configuration. In the framework of ab-initio atomistic thermodynamics, we argue that the anatase TiO{sub 2} prefers a defected O layer termination in the [001] direction. The obtained electronic structures indicate that H doping in the bulk creates the empty mid-gap state below the conduction band and hence decreases the band gap of the system. This phenomenon may explain the enhanced photocatalytic activity of the anatase TiO{sub 2} (001) surface after hydrogenation.
Authors:
;  [1] ;  [2] ;  [3]
  1. Superconductivity Research Laboratory (SRL), Department of Physics, University of Tehran, North Kargar Ave., P.O. Box 14395-547, Tehran (Iran, Islamic Republic of)
  2. Departement of Physics, Isfahan University of Technology, 84156 83111, Isfahan (Iran, Islamic Republic of)
  3. Department of Physics, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of)
Publication Date:
OSTI Identifier:
22251186
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 4; Journal Issue: 2; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ELECTRONIC STRUCTURE; HYDROGEN; HYDROGENATION; OXYGEN; PHOTOCATALYSIS; SURFACES; THERMODYNAMICS; TITANIUM OXIDES