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

Title: Gold, Copper, and Platinum Nanoparticles Dispersed on CeOx/TiO2(110) Surfaces: High Water-Gas Shift Activity and the Nature of the Mixed-Metal Oxide at the Nanometer Level

Abstract

At small coverages of ceria on TiO{sub 2}(110), the CeO{sub x} nanoparticles have an unusual coordination mode. Scanning tunneling microscopy and density-functional calculations point to the presence of Ce{sub 2}O{sub 3} dimers, which form diagonal arrays that have specific orientations of 0, 24, and 42{sup o} with respect to the [1 -1 0] direction of the titania substrate. At high coverages of ceria on TiO{sub 2}(110), the surface exhibits two types of terraces. In one type, the morphology is not very different from that observed at low ceria coverage. However, in the second type of terrace, there is a compact array of ceria particles with structures that do not match the structures of CeO{sub 2}(111) or CeO{sub 2}(110). The titania substrate imposes on the ceria nanoparticles nontypical coordination modes, enhancing their chemical reactivity. This phenomenon leads to a larger dispersion of supported metal nanoparticles (M = Au, Cu, Pt) and makes possible the direct participation of the oxide in catalytic reactions. The M/CeO{sub x}/TiO{sub 2}(110) surfaces display an extremely high catalytic activity for the water-gas shift reaction that follows the sequence Au/CeO{sub x}/TiO{sub 2}(110) < Cu/CeO{sub x}/TiO{sub 2}(110) < Pt/CeO{sub x}/TiO{sub 2}(110). For low coverages of Cu and CeO{sub x},more » Cu/CeO{sub x}/TiO{sub 2}(110) is 8-12 times more active than Cu(111) or Cu/ZnO industrial catalysts. In the M/CeO{sub x}/TiO{sub 2}(110) systems, there is a strong coupling of the chemical properties of the admetal and the mixed-metal oxide: The adsorption and dissociation of water probably take place on the oxide, CO adsorbs on the admetal nanoparticles, and all subsequent reaction steps occur at the oxide-admetal interface. The high catalytic activity of the M/CeO{sub x}/TiO{sub 2}(110) surfaces reflects the unique properties of the mixed-metal oxide at the nanometer level.« less

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
DOE - OFFICE OF SCIENCE
OSTI Identifier:
1019827
Report Number(s):
BNL-95673-2011-JA
Journal ID: ISSN 0002-7863; JACSAT; TRN: US201115%%463
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 132; Journal Issue: 1; Journal ID: ISSN 0002-7863
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ADSORPTION; CATALYSTS; CHEMICAL PROPERTIES; COPPER; DIMERS; DISSOCIATION; GOLD; MORPHOLOGY; OXIDES; PLATINUM; SCANNING TUNNELING MICROSCOPY; SUBSTRATES; WATER; WATER GAS; national synchrotron light source

Citation Formats

Park, J, Graciani, J, Evans, J, Stacchiola, D, Senanayake, S, Barrio, L, Liu, P, Fdez Sanz, J, Hrbek, J, and Rodriguez, J. Gold, Copper, and Platinum Nanoparticles Dispersed on CeOx/TiO2(110) Surfaces: High Water-Gas Shift Activity and the Nature of the Mixed-Metal Oxide at the Nanometer Level. United States: N. p., 2010. Web. doi:10.1021/ja9087677.
Park, J, Graciani, J, Evans, J, Stacchiola, D, Senanayake, S, Barrio, L, Liu, P, Fdez Sanz, J, Hrbek, J, & Rodriguez, J. Gold, Copper, and Platinum Nanoparticles Dispersed on CeOx/TiO2(110) Surfaces: High Water-Gas Shift Activity and the Nature of the Mixed-Metal Oxide at the Nanometer Level. United States. doi:10.1021/ja9087677.
Park, J, Graciani, J, Evans, J, Stacchiola, D, Senanayake, S, Barrio, L, Liu, P, Fdez Sanz, J, Hrbek, J, and Rodriguez, J. Fri . "Gold, Copper, and Platinum Nanoparticles Dispersed on CeOx/TiO2(110) Surfaces: High Water-Gas Shift Activity and the Nature of the Mixed-Metal Oxide at the Nanometer Level". United States. doi:10.1021/ja9087677.
@article{osti_1019827,
title = {Gold, Copper, and Platinum Nanoparticles Dispersed on CeOx/TiO2(110) Surfaces: High Water-Gas Shift Activity and the Nature of the Mixed-Metal Oxide at the Nanometer Level},
author = {Park, J and Graciani, J and Evans, J and Stacchiola, D and Senanayake, S and Barrio, L and Liu, P and Fdez Sanz, J and Hrbek, J and Rodriguez, J},
abstractNote = {At small coverages of ceria on TiO{sub 2}(110), the CeO{sub x} nanoparticles have an unusual coordination mode. Scanning tunneling microscopy and density-functional calculations point to the presence of Ce{sub 2}O{sub 3} dimers, which form diagonal arrays that have specific orientations of 0, 24, and 42{sup o} with respect to the [1 -1 0] direction of the titania substrate. At high coverages of ceria on TiO{sub 2}(110), the surface exhibits two types of terraces. In one type, the morphology is not very different from that observed at low ceria coverage. However, in the second type of terrace, there is a compact array of ceria particles with structures that do not match the structures of CeO{sub 2}(111) or CeO{sub 2}(110). The titania substrate imposes on the ceria nanoparticles nontypical coordination modes, enhancing their chemical reactivity. This phenomenon leads to a larger dispersion of supported metal nanoparticles (M = Au, Cu, Pt) and makes possible the direct participation of the oxide in catalytic reactions. The M/CeO{sub x}/TiO{sub 2}(110) surfaces display an extremely high catalytic activity for the water-gas shift reaction that follows the sequence Au/CeO{sub x}/TiO{sub 2}(110) < Cu/CeO{sub x}/TiO{sub 2}(110) < Pt/CeO{sub x}/TiO{sub 2}(110). For low coverages of Cu and CeO{sub x}, Cu/CeO{sub x}/TiO{sub 2}(110) is 8-12 times more active than Cu(111) or Cu/ZnO industrial catalysts. In the M/CeO{sub x}/TiO{sub 2}(110) systems, there is a strong coupling of the chemical properties of the admetal and the mixed-metal oxide: The adsorption and dissociation of water probably take place on the oxide, CO adsorbs on the admetal nanoparticles, and all subsequent reaction steps occur at the oxide-admetal interface. The high catalytic activity of the M/CeO{sub x}/TiO{sub 2}(110) surfaces reflects the unique properties of the mixed-metal oxide at the nanometer level.},
doi = {10.1021/ja9087677},
journal = {Journal of the American Chemical Society},
issn = {0002-7863},
number = 1,
volume = 132,
place = {United States},
year = {2010},
month = {1}
}