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

Title: Gold Nanoparticles on Ceria: Importance of O Vacancies in the Activation of Gold

Abstract

Synchrotron-based techniques (high-resolution photoemission, in-situ X-ray absorption spectroscopy, and time-resolved X-ray diffraction) have been used to study the destruction of SO{sub 2} and the water-gas shift (WGS, CO + H{sub 2}O {yields} H{sub 2} + CO{sub 2}) reaction on a series of gold/ceria systems. The adsorption and chemistry of SO{sub 2} was investigated on Au/CeO{sub 2}(111) and AuO{sub x} /CeO{sub 2} surfaces. The heat of adsorption of the molecule on Au nanoparticles supported on stoichiometric CeO{sub 2}(111) was 4-7 kcal/mol larger than on Au(111). However, there was negligible dissociation of SO{sub 2} on the Au/CeO{sub 2}(111) surfaces. The full decomposition of SO{sub 2} was observed only after introducing O vacancies in the ceria support. AuO{sub x} /CeO{sub 2} surfaces were found to be much less chemically active than Au/CeO{sub 2}(111) or Au/CeO{sub 2-x} (111) surfaces. In a separate set of experiments, in-situ time-resolved X-ray diffraction and X-ray absorption spectroscopy were used to monitor the behavior of nanostructured (Au + AuO{sub x})-CeO{sub 2} catalysts under the WGS reaction. At temperatures above 250 C, a complete AuO{sub x} {yields} Au transformation was observed with high catalytic activity. Photoemission results for the oxidation and reduction of Au nanoparticles supported on rough ceria filmsmore » or a CeO{sub 2}(111) single crystal corroborate that cationic Au{sup {delta}+} species cannot be the key sites responsible for the WGS activity at high temperatures. The active sites in (Au + AuO{sub x})/ceria catalysts should involve pure gold nanoparticles in contact with O vacancies of the oxide.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
929928
Report Number(s):
BNL-80522-2008-JA
TRN: US200822%%938
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Topics in Catalysis; Journal Volume: 44; Journal Issue: 39449
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; GOLD; NANOSTRUCTURES; CERIUM OXIDES; CATALYST SUPPORTS; VACANCIES; OXYGEN; CHEMICAL ACTIVATION; CATALYTIC EFFECTS; SULFUR DIOXIDE; DECOMPOSITION; SHIFT PROCESSES; WATER GAS; ADSORPTION HEAT; national synchrotron light source

Citation Formats

Rodriguez,J., Wang, X., Liu, P., Wen, W., Hanson, J., Hrbek, J., Perez, M., and Evans, J. Gold Nanoparticles on Ceria: Importance of O Vacancies in the Activation of Gold. United States: N. p., 2007. Web. doi:10.1007/s11244-007-0280-1.
Rodriguez,J., Wang, X., Liu, P., Wen, W., Hanson, J., Hrbek, J., Perez, M., & Evans, J. Gold Nanoparticles on Ceria: Importance of O Vacancies in the Activation of Gold. United States. doi:10.1007/s11244-007-0280-1.
Rodriguez,J., Wang, X., Liu, P., Wen, W., Hanson, J., Hrbek, J., Perez, M., and Evans, J. Mon . "Gold Nanoparticles on Ceria: Importance of O Vacancies in the Activation of Gold". United States. doi:10.1007/s11244-007-0280-1.
@article{osti_929928,
title = {Gold Nanoparticles on Ceria: Importance of O Vacancies in the Activation of Gold},
author = {Rodriguez,J. and Wang, X. and Liu, P. and Wen, W. and Hanson, J. and Hrbek, J. and Perez, M. and Evans, J.},
abstractNote = {Synchrotron-based techniques (high-resolution photoemission, in-situ X-ray absorption spectroscopy, and time-resolved X-ray diffraction) have been used to study the destruction of SO{sub 2} and the water-gas shift (WGS, CO + H{sub 2}O {yields} H{sub 2} + CO{sub 2}) reaction on a series of gold/ceria systems. The adsorption and chemistry of SO{sub 2} was investigated on Au/CeO{sub 2}(111) and AuO{sub x} /CeO{sub 2} surfaces. The heat of adsorption of the molecule on Au nanoparticles supported on stoichiometric CeO{sub 2}(111) was 4-7 kcal/mol larger than on Au(111). However, there was negligible dissociation of SO{sub 2} on the Au/CeO{sub 2}(111) surfaces. The full decomposition of SO{sub 2} was observed only after introducing O vacancies in the ceria support. AuO{sub x} /CeO{sub 2} surfaces were found to be much less chemically active than Au/CeO{sub 2}(111) or Au/CeO{sub 2-x} (111) surfaces. In a separate set of experiments, in-situ time-resolved X-ray diffraction and X-ray absorption spectroscopy were used to monitor the behavior of nanostructured (Au + AuO{sub x})-CeO{sub 2} catalysts under the WGS reaction. At temperatures above 250 C, a complete AuO{sub x} {yields} Au transformation was observed with high catalytic activity. Photoemission results for the oxidation and reduction of Au nanoparticles supported on rough ceria films or a CeO{sub 2}(111) single crystal corroborate that cationic Au{sup {delta}+} species cannot be the key sites responsible for the WGS activity at high temperatures. The active sites in (Au + AuO{sub x})/ceria catalysts should involve pure gold nanoparticles in contact with O vacancies of the oxide.},
doi = {10.1007/s11244-007-0280-1},
journal = {Topics in Catalysis},
number = 39449,
volume = 44,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}