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Title: Adsorption and decomposition of H{sub 2}S on MgO(100), NiMgO(100), and ZnO(0001) surfaces: A first-principles density functional study

Abstract

The adsorption and dissociation of H{sub 2}S on MgO(100), Ni-doped MgO(100), and ZnO(0001) was studied using first-principles density-functional calculations (DFT-GGA) and periodic supercells. The bonding of H{sub 2}S and its S-containing dissociated species (HS and S) is substantially stronger on ZnO(0001) than on MgO(100), making dissociation easier on zinc oxide. This behavior can be explained by the smaller ionicity in ZnO, which leads to a larger electron density around the Zn atoms and a larger reactivity toward S-containing molecules. Replacing some of the metal centers of MgO(100) with Ni atoms enhances the binding of S-containing species through new electronic states associated with the Ni 3d levels and located above the occupied {l_brace}O 2p + Mg 3s{r_brace} bands. In addition, structural defects, like steps, expose metal centers with lower coordination and larger reactivity than pentacoordinated Mg atoms in MgO(100). A simple model based on perturbation theory and band-orbital mixing is able to explain the differences in the reactivity of MgO(100) and ZnO(0001) and the behavior of other oxides (Al{sub 2}O{sub 3}, Cr{sub 2}O{sub 3}, Cr{sub 3}O{sub 4}, Cu{sub 2}O) in the presence of sulfur-containing molecules. The model predicts a negative correlation between the reactivity of the oxides and the size ofmore » the electronic band gap, with the chemical activity of an oxide depending mainly on how well its bands mix with the orbitals of H{sub 2}S. The electrostatic interactions between the Madelung field of the oxide and the dipole moment of the molecule play only a secondary role in bonding.« less

Authors:
;
Publication Date:
Research Org.:
Brookhaven National Lab., Upton, NY (US)
Sponsoring Org.:
USDOE
OSTI Identifier:
20030681
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical
Additional Journal Information:
Journal Volume: 104; Journal Issue: 15; Other Information: PBD: 20 Apr 2000; Journal ID: ISSN 1089-5647
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 01 COAL, LIGNITE, AND PEAT; 02 PETROLEUM; 03 NATURAL GAS; HYDROGEN SULFIDES; ADSORPTION; MAGNESIUM OXIDES; ZINC OXIDES; NICKEL COMPOUNDS; DISSOCIATION; CATALYSTS; POISONING; FOSSIL FUELS; DESULFURIZATION

Citation Formats

Rodriguez, J A, and Maiti, A. Adsorption and decomposition of H{sub 2}S on MgO(100), NiMgO(100), and ZnO(0001) surfaces: A first-principles density functional study. United States: N. p., 2000. Web. doi:10.1021/jp000011e.
Rodriguez, J A, & Maiti, A. Adsorption and decomposition of H{sub 2}S on MgO(100), NiMgO(100), and ZnO(0001) surfaces: A first-principles density functional study. United States. doi:10.1021/jp000011e.
Rodriguez, J A, and Maiti, A. Thu . "Adsorption and decomposition of H{sub 2}S on MgO(100), NiMgO(100), and ZnO(0001) surfaces: A first-principles density functional study". United States. doi:10.1021/jp000011e.
@article{osti_20030681,
title = {Adsorption and decomposition of H{sub 2}S on MgO(100), NiMgO(100), and ZnO(0001) surfaces: A first-principles density functional study},
author = {Rodriguez, J A and Maiti, A},
abstractNote = {The adsorption and dissociation of H{sub 2}S on MgO(100), Ni-doped MgO(100), and ZnO(0001) was studied using first-principles density-functional calculations (DFT-GGA) and periodic supercells. The bonding of H{sub 2}S and its S-containing dissociated species (HS and S) is substantially stronger on ZnO(0001) than on MgO(100), making dissociation easier on zinc oxide. This behavior can be explained by the smaller ionicity in ZnO, which leads to a larger electron density around the Zn atoms and a larger reactivity toward S-containing molecules. Replacing some of the metal centers of MgO(100) with Ni atoms enhances the binding of S-containing species through new electronic states associated with the Ni 3d levels and located above the occupied {l_brace}O 2p + Mg 3s{r_brace} bands. In addition, structural defects, like steps, expose metal centers with lower coordination and larger reactivity than pentacoordinated Mg atoms in MgO(100). A simple model based on perturbation theory and band-orbital mixing is able to explain the differences in the reactivity of MgO(100) and ZnO(0001) and the behavior of other oxides (Al{sub 2}O{sub 3}, Cr{sub 2}O{sub 3}, Cr{sub 3}O{sub 4}, Cu{sub 2}O) in the presence of sulfur-containing molecules. The model predicts a negative correlation between the reactivity of the oxides and the size of the electronic band gap, with the chemical activity of an oxide depending mainly on how well its bands mix with the orbitals of H{sub 2}S. The electrostatic interactions between the Madelung field of the oxide and the dipole moment of the molecule play only a secondary role in bonding.},
doi = {10.1021/jp000011e},
journal = {Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical},
issn = {1089-5647},
number = 15,
volume = 104,
place = {United States},
year = {2000},
month = {4}
}