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

Title: Catalysis by Design - Theoretical and Experimental Studies of Model Catalysts

Abstract

The development of new catalytic materials is still dominated by trial and error methods, even though the experimental and theoretical bases for their characterization have improved dramatically in recent years. Although it has been successful, the empirical development of catalytic materials is time consuming and expensive with no guarantee of success. We have been exploring computationally complex but experimentally simple systems to establish a 'catalysis by design' protocol that combines the power of theory and experiment. We hope to translate the fundamental insights directly into a complete catalyst system that is technologically relevant. The essential component of this approach is that the catalysts are iteratively examined by both theoretical and experimental methods. This approach involves state-of-the-art first principle density functional theory calculations, experimental design of catalyst sites, and sub-Angstrom resolution imaging with an aberration-corrected electron microscope to characterize the microstructure. We are employing this approach to understand the catalytic sites in oxidation and lean NOx catalysts. The model material for the oxidation catalyst system is Pt/Al2O3 and that for lean NOx catalysis is Ag/Al2O3. We present our initial results on theoretical and experimental studies of the oxidation and reactivity of catalyst clusters towards O, CO, and NOx. Our theoretical studiesmore » indicate that the reaction energetics are strongly dependent on the size of the clusters as well as the extent of oxidation of the clusters. We speculate that the energetics of CO and NO oxidation may be more favorable on the oxidized clusters than on the pure Pt clusters because of the weakened adsorption of the reactants. Experimentally, we have synthesized supported catalysts that contain small metal particles that mimic the theoretical models. We have also synthesized various supported catalysts with larger metal particles. We have studied CO oxidations on these catalysts and the results (including microstructural changes in Pt particles) will also be presented. In addition, we will summarize the results of our study of microstructural changes in supported catalysts, especially Ag/Al2O3, exposed to simulated lean NOx exhaust via the ORNL ex situ reactor in order to determine the impact of operating conditions on the catalyst.« less

Authors:
 [1];  [1];  [1];  [1];  [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
930912
DOE Contract Number:  
AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Journal Volume: 1; Conference: Society of Automotive Engineers Congress, Detroit, MI, USA, 20070416, 20070419
Country of Publication:
United States
Language:
English

Citation Formats

Narula, Chaitanya Kumar, DeBusk, Melanie Moses, Xu, Ye, Blom, Douglas Allen, Allard Jr, Lawrence Frederick, and Shelton Jr, William Allison. Catalysis by Design - Theoretical and Experimental Studies of Model Catalysts. United States: N. p., 2007. Web. doi:10.4271/2007-01-1018.
Narula, Chaitanya Kumar, DeBusk, Melanie Moses, Xu, Ye, Blom, Douglas Allen, Allard Jr, Lawrence Frederick, & Shelton Jr, William Allison. Catalysis by Design - Theoretical and Experimental Studies of Model Catalysts. United States. doi:10.4271/2007-01-1018.
Narula, Chaitanya Kumar, DeBusk, Melanie Moses, Xu, Ye, Blom, Douglas Allen, Allard Jr, Lawrence Frederick, and Shelton Jr, William Allison. Mon . "Catalysis by Design - Theoretical and Experimental Studies of Model Catalysts". United States. doi:10.4271/2007-01-1018.
@article{osti_930912,
title = {Catalysis by Design - Theoretical and Experimental Studies of Model Catalysts},
author = {Narula, Chaitanya Kumar and DeBusk, Melanie Moses and Xu, Ye and Blom, Douglas Allen and Allard Jr, Lawrence Frederick and Shelton Jr, William Allison},
abstractNote = {The development of new catalytic materials is still dominated by trial and error methods, even though the experimental and theoretical bases for their characterization have improved dramatically in recent years. Although it has been successful, the empirical development of catalytic materials is time consuming and expensive with no guarantee of success. We have been exploring computationally complex but experimentally simple systems to establish a 'catalysis by design' protocol that combines the power of theory and experiment. We hope to translate the fundamental insights directly into a complete catalyst system that is technologically relevant. The essential component of this approach is that the catalysts are iteratively examined by both theoretical and experimental methods. This approach involves state-of-the-art first principle density functional theory calculations, experimental design of catalyst sites, and sub-Angstrom resolution imaging with an aberration-corrected electron microscope to characterize the microstructure. We are employing this approach to understand the catalytic sites in oxidation and lean NOx catalysts. The model material for the oxidation catalyst system is Pt/Al2O3 and that for lean NOx catalysis is Ag/Al2O3. We present our initial results on theoretical and experimental studies of the oxidation and reactivity of catalyst clusters towards O, CO, and NOx. Our theoretical studies indicate that the reaction energetics are strongly dependent on the size of the clusters as well as the extent of oxidation of the clusters. We speculate that the energetics of CO and NO oxidation may be more favorable on the oxidized clusters than on the pure Pt clusters because of the weakened adsorption of the reactants. Experimentally, we have synthesized supported catalysts that contain small metal particles that mimic the theoretical models. We have also synthesized various supported catalysts with larger metal particles. We have studied CO oxidations on these catalysts and the results (including microstructural changes in Pt particles) will also be presented. In addition, we will summarize the results of our study of microstructural changes in supported catalysts, especially Ag/Al2O3, exposed to simulated lean NOx exhaust via the ORNL ex situ reactor in order to determine the impact of operating conditions on the catalyst.},
doi = {10.4271/2007-01-1018},
journal = {},
number = ,
volume = 1,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share: