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Research Highlight

In Situ Vibrational Spectroscopy Provides First Direct Evidence for the Roles of Hydrogen Species in Selective Hydrogenation over Ceria

Topic: Materials

Scientific Achievement

In situ inelastic neutron scattering (INS) and IR spectroscopy provide the first direct evidence for the catalytic roles of cerium hydride (Ce-H) and hydroxyl group (OH) groups in acetylene hydrogenation over ceria as a function of the density of oxygen vacancies.

Significance and Impact

Revealing reaction mechanism for selective hydrogenation over ceria provide insights into the design of more active, selective and stable ceria-based catalysts for hydrogenation reactions.

Research Details

  • In situ INS results provide that not only Ce-H but also surface atomic hydrogen species on the reduced ceria surface can participate in acetylene hydrogenation.
  • In situ DRIFTS results show that bridged OH groups on both the oxidized and reduced ceria are active for selective hydrogenation of acetylene.
  • The surface Ce-H is more reactive than the co-existing OH species on the reduced ceria surface, but over reduction of ceria results in strongly bound species that may lead to catalyst deactivation

Discriminating the Role of Surface Hydride and Hydroxyl for Acetylene Semi-hydrogenation over Ceria Through in situ Neutron and Infrared spectroscopy  ACS Catal. 2020, DOI:10.1021/acscatal.0c00808.