Shaped Ceria Nanocrystals Catalyze Efficient and Selective Para-Hydrogen-Enhanced Polarization.
Zhao, Evan W
Hagelin-Weaver, Helena E
Bowers, Clifford R
Angew Chem Int Ed Engl
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Zhao, E. W., Zheng, H., Zhou, R., Hagelin-Weaver, H. E., & Bowers, C. R. (2015). Shaped Ceria Nanocrystals Catalyze Efficient and Selective Para-Hydrogen-Enhanced Polarization.. Angew Chem Int Ed Engl, 54 (48), 14270-14275. https://doi.org/10.1002/anie.201506045
Intense para-hydrogen-enhanced NMR signals are observed in the hydrogenation of propene and propyne over ceria nanocubes, nano-octahedra, and nanorods. The well-defined ceria shapes, synthesized by a hydrothermal method, expose different crystalline facets with various oxygen vacancy densities, which are known to play a role in hydrogenation and oxidation catalysis. While the catalytic activity of the hydrogenation of propene over ceria is strongly facet-dependent, the pairwise selectivity is low (2.4% at 375 °C), which is consistent with stepwise H atom transfer, and it is the same for all three nanocrystal shapes. Selective semi-hydrogenation of propyne over ceria nanocubes yields hyperpolarized propene with a similar pairwise selectivity of (2.7% at 300 °C), indicating product formation predominantly by a non-pairwise addition. Ceria is also shown to be an efficient pairwise replacement catalyst for propene.
ACS‐PRF. Grant Number: 52258‐ND5 NSF. Grant Number: CHE‐1507230
External DOI: https://doi.org/10.1002/anie.201506045
This record's URL: https://www.repository.cam.ac.uk/handle/1810/319163
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