Abstract
Ceria has recently shown intriguing hydrogenation reactivity in catalyzing alkyne selectively to alkenes. However, the mechanism of the hydrogenation reaction, especially the activation of H2, remains experimentally elusive. In this work, we report the first direct spectroscopy evidence for the presence of both surface and bulk Ce-H species upon H2 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 H2 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. The finding of this work has significant implications for understanding catalysis by ceria in both hydrogenation and redox reactions where hydrogen is involved.
| Original language | English |
|---|---|
| Pages (from-to) | 9721-9727 |
| Number of pages | 7 |
| Journal | Journal of the American Chemical Society |
| Volume | 139 |
| Issue number | 28 |
| DOIs | |
| State | Published - Jul 19 2017 |
Funding
This research is sponsored by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division. Part of the work including in situ IR and Raman spectroscopy and H2-TPR measurement was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.