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Title: Direct Neutron Spectroscopy Observation of Cerium Hydride Species on a Cerium Oxide Catalyst

Ceria has recently shown intriguing hydrogenation reactivity in catalyzing alkyne selectively to alkenes. However, the mechanism of the hydrogenation reaction, especially the activation of H 2, remains experimentally elusive. In this paper, we report the first direct spectroscopy evidence for the presence of both surface and bulk Ce–H species upon H 2 dissociation over ceria via in situ inelastic neutron scattering spectroscopy. Combined with in situ ambient-pressure X-ray photoelectron spectroscopy, IR, and Raman spectroscopic studies, the results together point to a heterolytic dissociation mechanism of H 2 over ceria, leading to either homolytic products (surface OHs) on a close-to-stoichiometric ceria surface or heterolytic products (Ce–H and OH) with the presence of induced oxygen vacancies in ceria. Finally, the finding of this work has significant implications for understanding catalysis by ceria in both hydrogenation and redox reactions where hydrogen is involved.
Authors:
ORCiD logo [1] ;  [2] ; ORCiD logo [3] ;  [2] ;  [1] ;  [3] ;  [3] ; ORCiD logo [4] ;  [2]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Science Division. Center for Nanophase Materials Sciences
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical and Engineering Materials Division
  3. Univ. of Kansas, Lawrence, KS (United States). Dept. of Chemical and Petroleum Engineering. Dept. of Chemistry
  4. Univ. of Tennessee, Oak Ridge, TN (United States). Joint Inst. for Computational Sciences
Publication Date:
Grant/Contract Number:
AC05-00OR22725; SC0014561
Type:
Accepted Manuscript
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 139; Journal Issue: 28; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society (ACS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE Laboratory Directed Research and Development (LDRD) Program
Contributing Orgs:
Univ. of Tennessee, Oak Ridge, TN (United States)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1376480