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Title: “Intelligent” Pt Catalysts Studied on High-Surface-Area CaTiO 3 Films

Abstract

CaTiO 3-supported Pt is sometimes referred to as an “Intelligent” catalyst because Pt can reversibly leave or enter the perovskite lattice following high-temperature reduction or oxidation; however, slow egress-ingress kinetics associated with large perovskite crystallites make these systems impractical. In this study, thin films (~1 nm) of CaTiO 3 were deposited onto MgAl 2O 4 and then examined as catalyst supports for Pt and Pd. While Pd/CaTiO 3/MgAl 2O 4 showed adsorption and CO-oxidation properties that were essentially the same as Pd/MgAl 2O 4, the Pt/CaTiO 3/MgAl 2O 4 catalyst exhibited evidence for strong support interactions. Pt/CaTiO 3/MgAl 2O 4 showed high activity for CO oxidation following reduction at 1073 K, even though CO adsorption was suppressed; but the catalysts were dramatically less active after oxidation at 1073 K and reduction at 773 K. Both Pt/CaTiO 3/MgAl 2O 4 and a catalyst formed by ex-solution of CaTi 0.95Pt 0.05O 3 exhibited very low rates for toluene hydrogenation in comparison to Pt/MgAl 2O 4. Scanning Transmission Electron Microscopy (STEM) and Energy Dispersive Spectroscopy (EDS) showed that the CaTiO 3 films uniformly covered the MgAl 2O 4 surface after both reduction and oxidation at 1073 K. Pt particles on reduced Pt/CaTiO 3/MgAlmore » 2O 4 exhibited an unusual rhombohedral shape and may be flat, a further indication of strong interactions between the metal and the support. Low Energy Ion Scattering (LEIS) indicated that high-temperature reduction caused a restructuring of the CaTiO 3. Lastly, the implications of these results for understanding catalysts formed by ex-solution of metals from a perovskite lattice are discussed.« less

Authors:
 [1];  [1];  [1];  [2];  [1];  [2];  [1]
  1. Univ. of Pennsylvania, Philadelphia, PA (United States)
  2. Lehigh Univ., Bethlehem, PA (United States)
Publication Date:
Research Org.:
Univ. of Pennsylvania, Philadelphia, PA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Chemical Sciences, Geosciences & Biosciences Division
Contributing Org.:
NSF National Nanotechnology Coordinated Infrastructure Program
OSTI Identifier:
1532462
Grant/Contract Number:  
FG02-13ER16380; SC0009440
Resource Type:
Accepted Manuscript
Journal Name:
ACS Catalysis
Additional Journal Information:
Journal Name: ACS Catalysis; Journal ID: ISSN 2155-5435
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 42 ENGINEERING; CO oxidation; Toluene hydrogenation; Atomic Layer Deposition (ALD); “Intelligent” catalyst; Pt; Pd; CaTiO3

Citation Formats

Lin, Chao, Foucher, Alexandre C., Ji, Yichen, Curran, Christopher D., Stach, Eric A., McIntosh, Steven, and Gorte, Raymond J. “Intelligent” Pt Catalysts Studied on High-Surface-Area CaTiO3 Films. United States: N. p., 2019. Web. doi:10.1021/acscatal.9b01278.
Lin, Chao, Foucher, Alexandre C., Ji, Yichen, Curran, Christopher D., Stach, Eric A., McIntosh, Steven, & Gorte, Raymond J. “Intelligent” Pt Catalysts Studied on High-Surface-Area CaTiO3 Films. United States. doi:10.1021/acscatal.9b01278.
Lin, Chao, Foucher, Alexandre C., Ji, Yichen, Curran, Christopher D., Stach, Eric A., McIntosh, Steven, and Gorte, Raymond J. Mon . "“Intelligent” Pt Catalysts Studied on High-Surface-Area CaTiO3 Films". United States. doi:10.1021/acscatal.9b01278.
@article{osti_1532462,
title = {“Intelligent” Pt Catalysts Studied on High-Surface-Area CaTiO3 Films},
author = {Lin, Chao and Foucher, Alexandre C. and Ji, Yichen and Curran, Christopher D. and Stach, Eric A. and McIntosh, Steven and Gorte, Raymond J.},
abstractNote = {CaTiO3-supported Pt is sometimes referred to as an “Intelligent” catalyst because Pt can reversibly leave or enter the perovskite lattice following high-temperature reduction or oxidation; however, slow egress-ingress kinetics associated with large perovskite crystallites make these systems impractical. In this study, thin films (~1 nm) of CaTiO3 were deposited onto MgAl2O4 and then examined as catalyst supports for Pt and Pd. While Pd/CaTiO3/MgAl2O4 showed adsorption and CO-oxidation properties that were essentially the same as Pd/MgAl2O4, the Pt/CaTiO3/MgAl2O4 catalyst exhibited evidence for strong support interactions. Pt/CaTiO3/MgAl2O4 showed high activity for CO oxidation following reduction at 1073 K, even though CO adsorption was suppressed; but the catalysts were dramatically less active after oxidation at 1073 K and reduction at 773 K. Both Pt/CaTiO3/MgAl2O4 and a catalyst formed by ex-solution of CaTi0.95Pt0.05O3 exhibited very low rates for toluene hydrogenation in comparison to Pt/MgAl2O4. Scanning Transmission Electron Microscopy (STEM) and Energy Dispersive Spectroscopy (EDS) showed that the CaTiO3 films uniformly covered the MgAl2O4 surface after both reduction and oxidation at 1073 K. Pt particles on reduced Pt/CaTiO3/MgAl2O4 exhibited an unusual rhombohedral shape and may be flat, a further indication of strong interactions between the metal and the support. Low Energy Ion Scattering (LEIS) indicated that high-temperature reduction caused a restructuring of the CaTiO3. Lastly, the implications of these results for understanding catalysts formed by ex-solution of metals from a perovskite lattice are discussed.},
doi = {10.1021/acscatal.9b01278},
journal = {ACS Catalysis},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {7}
}

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This content will become publicly available on July 8, 2020
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