skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Structural Investigation of Au Catalysts on TiO2-SiO2 Supports: Nature of the Local Structure of Ti and Au Atoms by EXAFS and XANES

Abstract

X-ray absorption spectroscopy (XAS) was utilized to investigate both the Au particle size on several supports composed by silica and titanium oxide, and the coordination of TiO2 in the support phase. Particularly, we wanted to utilize the technique to probe mixing in the support phase, by using different synthetic methods such as by functionalizing silica or by ALD (atomic layer deposition) techniques as prepared in our laboratories, and the growth and stability of Au nanoparticles deposited on these supports. The study using cosynthesis techniques to dope bulk mesoporous SiO2 with TiO2 resulted in TiO2 being dispersed in the SiO2 matrix; however, a second phase starts forming as the TiO2 content increases as indicated by the EXAFS Ti-O shell shift in position and increase of coordination number. On the supports prepared by cosynthesis, Au particles were smaller and more stable. The study using the surface sol-gel technique for deposition of single monolayers of an oxide such as TiO2 produced Ti environments in which the Ti-O shell and the next two Ti-Ti shells lie on the same position as expected for an anatase structure. Although undercoordinated, the presence of the Ti-Ti shells indicate that the titania species are not molecularly dispersed onmore » the SiO2 surface as hypothesized, but there is indeed a cross-linking of the titania moieties.« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
960110
Report Number(s):
BNL-83096-2009-JA
Journal ID: ISSN 1932-7447; TRN: US201016%%1254
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physical Chemistry C; Journal Volume: 111; Journal Issue: 46
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION SPECTROSCOPY; ATOMS; CATALYSTS; COORDINATION NUMBER; CROSS-LINKING; DEPOSITION; OXIDES; PARTICLE SIZE; SILICA; STABILITY; TITANIUM OXIDES; SILICON OXIDES; national synchrotron light source

Citation Formats

Schwartz,V., Mullins, D., Yan, W., Zhu, H., Dai, S., and Overbury, S. Structural Investigation of Au Catalysts on TiO2-SiO2 Supports: Nature of the Local Structure of Ti and Au Atoms by EXAFS and XANES. United States: N. p., 2007. Web. doi:10.1021/jp074426c.
Schwartz,V., Mullins, D., Yan, W., Zhu, H., Dai, S., & Overbury, S. Structural Investigation of Au Catalysts on TiO2-SiO2 Supports: Nature of the Local Structure of Ti and Au Atoms by EXAFS and XANES. United States. doi:10.1021/jp074426c.
Schwartz,V., Mullins, D., Yan, W., Zhu, H., Dai, S., and Overbury, S. Mon . "Structural Investigation of Au Catalysts on TiO2-SiO2 Supports: Nature of the Local Structure of Ti and Au Atoms by EXAFS and XANES". United States. doi:10.1021/jp074426c.
@article{osti_960110,
title = {Structural Investigation of Au Catalysts on TiO2-SiO2 Supports: Nature of the Local Structure of Ti and Au Atoms by EXAFS and XANES},
author = {Schwartz,V. and Mullins, D. and Yan, W. and Zhu, H. and Dai, S. and Overbury, S.},
abstractNote = {X-ray absorption spectroscopy (XAS) was utilized to investigate both the Au particle size on several supports composed by silica and titanium oxide, and the coordination of TiO2 in the support phase. Particularly, we wanted to utilize the technique to probe mixing in the support phase, by using different synthetic methods such as by functionalizing silica or by ALD (atomic layer deposition) techniques as prepared in our laboratories, and the growth and stability of Au nanoparticles deposited on these supports. The study using cosynthesis techniques to dope bulk mesoporous SiO2 with TiO2 resulted in TiO2 being dispersed in the SiO2 matrix; however, a second phase starts forming as the TiO2 content increases as indicated by the EXAFS Ti-O shell shift in position and increase of coordination number. On the supports prepared by cosynthesis, Au particles were smaller and more stable. The study using the surface sol-gel technique for deposition of single monolayers of an oxide such as TiO2 produced Ti environments in which the Ti-O shell and the next two Ti-Ti shells lie on the same position as expected for an anatase structure. Although undercoordinated, the presence of the Ti-Ti shells indicate that the titania species are not molecularly dispersed on the SiO2 surface as hypothesized, but there is indeed a cross-linking of the titania moieties.},
doi = {10.1021/jp074426c},
journal = {Journal of Physical Chemistry C},
number = 46,
volume = 111,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}