Abstract
Density functional theory and low energy ion scattering spectroscopy were applied to study the mechanism of oxygen dissociation on the SrO-terminated surfaces of strontium titanate (SrTiO3) and iron-doped strontium titanate (SrTi1-xFexO3Δ). Our study reveals that while O2 dissociation is not favored on the SrO-terminated perovskite surface, oxygen vacancies can act as active sites and catalyze the O-O bond cleavage. Electron transfer from lattice oxygen atoms to the O2 molecule, mediated by the subsurface transition metal cations, plays an important role in the resulting formation of surface superoxo species. The O2 molecule dissociates to produce oxygen ions, which are incorporated into the perovskite lattice, and highly active oxygen radicals on the perovskite surface, which further recombine to O2 molecules. Our focus on the SrO-terminated surface, rather than the TiO2 layer, which is presumed to be more catalytically active, was driven by experimental observation using low energy ion scattering spectroscopy, which reveals that the surface of SrTiO3 after high temperature heat treatment is SrO-terminated, and hence this is the surface that is technologically relevant for devices such as solid oxide fuel cells (SOFCs). Our study demonstrates that although the more active BO2-perovskite layer is not exposed at the gas-solid interface, the SrO-terminated surfaces also actively participate in oxygen exchange reaction.
| Original language | English |
|---|---|
| Pages (from-to) | 8273-8281 |
| Number of pages | 9 |
| Journal | Chemistry of Materials |
| Volume | 27 |
| Issue number | 24 |
| DOIs | |
| Publication status | Published - Dec 22 2015 |
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All Science Journal Classification (ASJC) codes
- Chemistry(all)
- Chemical Engineering(all)
- Materials Chemistry
Cite this
Oxygen Activation and Dissociation on Transition Metal Free Perovskite Surfaces. / Staykov, Aleksandar Tsekov; Tellez Lozano, Helena; Akbay, Taner; Druce, John William Richard; Ishihara, Tatsumi; Kilner, John.
In: Chemistry of Materials, Vol. 27, No. 24, 22.12.2015, p. 8273-8281.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Oxygen Activation and Dissociation on Transition Metal Free Perovskite Surfaces
AU - Staykov, Aleksandar Tsekov
AU - Tellez Lozano, Helena
AU - Akbay, Taner
AU - Druce, John William Richard
AU - Ishihara, Tatsumi
AU - Kilner, John
PY - 2015/12/22
Y1 - 2015/12/22
N2 - Density functional theory and low energy ion scattering spectroscopy were applied to study the mechanism of oxygen dissociation on the SrO-terminated surfaces of strontium titanate (SrTiO3) and iron-doped strontium titanate (SrTi1-xFexO3Δ). Our study reveals that while O2 dissociation is not favored on the SrO-terminated perovskite surface, oxygen vacancies can act as active sites and catalyze the O-O bond cleavage. Electron transfer from lattice oxygen atoms to the O2 molecule, mediated by the subsurface transition metal cations, plays an important role in the resulting formation of surface superoxo species. The O2 molecule dissociates to produce oxygen ions, which are incorporated into the perovskite lattice, and highly active oxygen radicals on the perovskite surface, which further recombine to O2 molecules. Our focus on the SrO-terminated surface, rather than the TiO2 layer, which is presumed to be more catalytically active, was driven by experimental observation using low energy ion scattering spectroscopy, which reveals that the surface of SrTiO3 after high temperature heat treatment is SrO-terminated, and hence this is the surface that is technologically relevant for devices such as solid oxide fuel cells (SOFCs). Our study demonstrates that although the more active BO2-perovskite layer is not exposed at the gas-solid interface, the SrO-terminated surfaces also actively participate in oxygen exchange reaction.
AB - Density functional theory and low energy ion scattering spectroscopy were applied to study the mechanism of oxygen dissociation on the SrO-terminated surfaces of strontium titanate (SrTiO3) and iron-doped strontium titanate (SrTi1-xFexO3Δ). Our study reveals that while O2 dissociation is not favored on the SrO-terminated perovskite surface, oxygen vacancies can act as active sites and catalyze the O-O bond cleavage. Electron transfer from lattice oxygen atoms to the O2 molecule, mediated by the subsurface transition metal cations, plays an important role in the resulting formation of surface superoxo species. The O2 molecule dissociates to produce oxygen ions, which are incorporated into the perovskite lattice, and highly active oxygen radicals on the perovskite surface, which further recombine to O2 molecules. Our focus on the SrO-terminated surface, rather than the TiO2 layer, which is presumed to be more catalytically active, was driven by experimental observation using low energy ion scattering spectroscopy, which reveals that the surface of SrTiO3 after high temperature heat treatment is SrO-terminated, and hence this is the surface that is technologically relevant for devices such as solid oxide fuel cells (SOFCs). Our study demonstrates that although the more active BO2-perovskite layer is not exposed at the gas-solid interface, the SrO-terminated surfaces also actively participate in oxygen exchange reaction.
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U2 - 10.1021/acs.chemmater.5b03263
DO - 10.1021/acs.chemmater.5b03263
M3 - Article
VL - 27
SP - 8273
EP - 8281
JO - Chemistry of Materials
JF - Chemistry of Materials
SN - 0897-4756
IS - 24
ER -