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In this communication, we report new oxide catalysts, including SiO2, γ-Al2O3, and CeO2 combined with 3d transition metal cocatalysts, which promote H2 adsorption, as a result of our exploration based on our hypothesis that an inhomogeneous electric field on the surface of the insulating oxide with high ionicity promotes OP conversion. The fraction of para-H2 on 5%Fe-loaded SiO2 powder reaches the equilibrium value at 77 K within 20 min. The activities of these catalysts are several times higher than those of benchmark catalysts such as Mn3O4. We suggest a mechanism by which the nuclear spin state of the adsorbed ortho-H2 is thermally excited by nuclear quadrupole interactions and the conversion is enhanced through nuclear spin relaxation.

Rights:

• Creative Commons BY Attribution 4.0 International
  

Keyword: hydrogen, ortho-para conversion, catalysts

Date published: 2026-03-26

Publisher: American Chemical Society (ACS)

Journal:

• The Journal of Physical Chemistry Letters (ISSN: 19487185) acs.jpclett.6c00357

Funding:

• JST-Mirai Program JPMJMI18A3
• Ministry of Education, Culture, Sports, Science and Technology JPMXP1225NM5175
• JFE 21st Century Foundation
• Japan Society for the Promotion of Science 23K23440
• Japan Society for the Promotion of Science 24K21813
• Iketani Science and Technology Foundation

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.1021/acs.jpclett.6c00357

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Updated at: 2026-03-27 09:07:48 +0900

Published on MDR: 2026-03-27 12:22:35 +0900