Abstract
Vanadium oxide (VOx) molecular species supported on high surface area oxide supports are active catalysts for oxidative transformations of organic molecules. Since the reactivity of VOx species depends on their molecular structure, the understanding and control of factors that determine their structure would be useful in surface molecular catalyst design. Reactive adsorption of vanadyl triisopropoxide (VOTP) to form monomeric VO x species on amorphous Al2O3 and SrTiO 3 (001) surfaces has been studied by X-ray photoelectron spectroscopy (XPS). Quantitative comparison of C(1s) and V(2p3/2) peak areas has been used to determine the number of isopropoxide ligands that are replaced by V-O surface bonds. On average, three V-O surface bonds are formed during adsorption on an amorphous Al2O3 surface, as expected in the formation of a tridentate, VO4 structure, typically assigned to monomeric, surface VOx species. On the SrTiO3 (001) surface, the number of V-O surface bonds depends on the oxygen density prior to reaction with VOTP. For adsorption on the SrTiO3 surface cleaned and oxygen-annealed in ultrahigh vacuum, the number of V-O surface bonds is ca. 2. When the SrTiO3 surface has been Ar-ion sputtered prior to VOTP adsorption, the number of V-O bonds is ca. 1. This study demonstrates that the atomic structure of the support can strongly influence the molecular nature of surface VOx species.
| Original language | English |
|---|---|
| Pages (from-to) | 177-187 |
| Number of pages | 11 |
| Journal | Topics in Catalysis |
| Volume | 57 |
| Issue number | 1-4 |
| DOIs | |
| Publication status | Published - Feb 2014 |
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Keywords
- Strontium titanate
- Surface structure
- Vanadium oxide
- XPS
ASJC Scopus subject areas
- Catalysis
- Chemistry(all)
Cite this
Influence of the metal oxide substrate structure on vanadium oxide monomer formation. / Johnson, Alexis M.; Quezada, Brian R.; Marks, Laurence D.; Stair, Peter C.
In: Topics in Catalysis, Vol. 57, No. 1-4, 02.2014, p. 177-187.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Influence of the metal oxide substrate structure on vanadium oxide monomer formation
AU - Johnson, Alexis M.
AU - Quezada, Brian R.
AU - Marks, Laurence D.
AU - Stair, Peter C
PY - 2014/2
Y1 - 2014/2
N2 - Vanadium oxide (VOx) molecular species supported on high surface area oxide supports are active catalysts for oxidative transformations of organic molecules. Since the reactivity of VOx species depends on their molecular structure, the understanding and control of factors that determine their structure would be useful in surface molecular catalyst design. Reactive adsorption of vanadyl triisopropoxide (VOTP) to form monomeric VO x species on amorphous Al2O3 and SrTiO 3 (001) surfaces has been studied by X-ray photoelectron spectroscopy (XPS). Quantitative comparison of C(1s) and V(2p3/2) peak areas has been used to determine the number of isopropoxide ligands that are replaced by V-O surface bonds. On average, three V-O surface bonds are formed during adsorption on an amorphous Al2O3 surface, as expected in the formation of a tridentate, VO4 structure, typically assigned to monomeric, surface VOx species. On the SrTiO3 (001) surface, the number of V-O surface bonds depends on the oxygen density prior to reaction with VOTP. For adsorption on the SrTiO3 surface cleaned and oxygen-annealed in ultrahigh vacuum, the number of V-O surface bonds is ca. 2. When the SrTiO3 surface has been Ar-ion sputtered prior to VOTP adsorption, the number of V-O bonds is ca. 1. This study demonstrates that the atomic structure of the support can strongly influence the molecular nature of surface VOx species.
AB - Vanadium oxide (VOx) molecular species supported on high surface area oxide supports are active catalysts for oxidative transformations of organic molecules. Since the reactivity of VOx species depends on their molecular structure, the understanding and control of factors that determine their structure would be useful in surface molecular catalyst design. Reactive adsorption of vanadyl triisopropoxide (VOTP) to form monomeric VO x species on amorphous Al2O3 and SrTiO 3 (001) surfaces has been studied by X-ray photoelectron spectroscopy (XPS). Quantitative comparison of C(1s) and V(2p3/2) peak areas has been used to determine the number of isopropoxide ligands that are replaced by V-O surface bonds. On average, three V-O surface bonds are formed during adsorption on an amorphous Al2O3 surface, as expected in the formation of a tridentate, VO4 structure, typically assigned to monomeric, surface VOx species. On the SrTiO3 (001) surface, the number of V-O surface bonds depends on the oxygen density prior to reaction with VOTP. For adsorption on the SrTiO3 surface cleaned and oxygen-annealed in ultrahigh vacuum, the number of V-O surface bonds is ca. 2. When the SrTiO3 surface has been Ar-ion sputtered prior to VOTP adsorption, the number of V-O bonds is ca. 1. This study demonstrates that the atomic structure of the support can strongly influence the molecular nature of surface VOx species.
KW - Strontium titanate
KW - Surface structure
KW - Vanadium oxide
KW - XPS
UR - http://www.scopus.com/inward/record.url?scp=84893695669&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84893695669&partnerID=8YFLogxK
U2 - 10.1007/s11244-013-0174-3
DO - 10.1007/s11244-013-0174-3
M3 - Article
AN - SCOPUS:84893695669
VL - 57
SP - 177
EP - 187
JO - Topics in Catalysis
JF - Topics in Catalysis
SN - 1022-5528
IS - 1-4
ER -