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Oxygen vacancies as active sites for H$_2$S dissociation on the rutile TiO$_2$(110) surface: a first-principles study


Wang, Fang; Wei, Shiqian; Zhang, Zhi; Patzke, Greta R; Zhou, Ying (2016). Oxygen vacancies as active sites for H$_2$S dissociation on the rutile TiO$_2$(110) surface: a first-principles study. Physical Chemistry Chemical Physics (PCCP), 18(9):6706-6712.

Abstract

Spin-polarized DFT+U computations have been performed to investigate the role of oxygen vacancies in dissociating H$_2$S on the rutile TiO$_2$(110) surface. A bridged O$_{2c}$ atom is demonstrated to be the most energetically favorable oxygen vacancy site, which makes V(O$_{2c}$) an electron donator center and induces an isolated defect level with narrowed band gaps. A H2S molecule is adsorbed dissociatively over V(O$_{2c}$), but molecularly on the perfect surface. For H$_2$S dissociation, the HS/H intermediate state reveals the best thermal stability on both defected and perfect surfaces. Moreover, potential energy surface analysis shows that V(O$_{2c}$) reduces markedly the energy barriers for the paths along H$_2$S dissociation. This indicates oxygen vacancies to be efficient trap centers for H$_2$S dissociation, as evidenced by a significant interfacial charge transfer promoted by vacancies. This work could provide insights into the role of oxygen vacancies in facilitating the decomposition of H$_2$S on rutile TiO$_2$(110) surface.

Abstract

Spin-polarized DFT+U computations have been performed to investigate the role of oxygen vacancies in dissociating H$_2$S on the rutile TiO$_2$(110) surface. A bridged O$_{2c}$ atom is demonstrated to be the most energetically favorable oxygen vacancy site, which makes V(O$_{2c}$) an electron donator center and induces an isolated defect level with narrowed band gaps. A H2S molecule is adsorbed dissociatively over V(O$_{2c}$), but molecularly on the perfect surface. For H$_2$S dissociation, the HS/H intermediate state reveals the best thermal stability on both defected and perfect surfaces. Moreover, potential energy surface analysis shows that V(O$_{2c}$) reduces markedly the energy barriers for the paths along H$_2$S dissociation. This indicates oxygen vacancies to be efficient trap centers for H$_2$S dissociation, as evidenced by a significant interfacial charge transfer promoted by vacancies. This work could provide insights into the role of oxygen vacancies in facilitating the decomposition of H$_2$S on rutile TiO$_2$(110) surface.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Chemistry
Dewey Decimal Classification:540 Chemistry
Language:English
Date:2016
Deposited On:30 Jan 2017 11:01
Last Modified:31 May 2017 07:00
Publisher:Royal Society of Chemistry
ISSN:1463-9076
Publisher DOI:https://doi.org/10.1039/C5CP06835E
PubMed ID:26875868

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