Hydrogen adsorption on two catalysts for the ortho- to parahydrogen conversion: Cr-doped silica and ferric oxide gel

Monika Hartl, Robert Chad Gillis, Luke Daemen, Daniel P Olds, Katherine Page, Stefan Carlson, Yongqiang Cheng, Thomas Hügle, Erik B Iverson, A J Ramirez-Cuesta, Yong Joong Lee, Günter Muhrer

Research output: Contribution to journalArticlepeer-review

20 Citations (SciVal)

Abstract

Molecular hydrogen exists in two spin-rotation coupled states: parahydrogen and orthohydrogen. Due to the variation of energy with rotational level, the occupation of ortho- and parahydrogen states is temperature dependent, with parahydrogen being the dominant species at low temperatures. The equilibrium at 20 K (99.8% parahydrogen) can be reached by natural conversion only after a lengthy process. With the use of a suitable catalyst, this process can be shortened significantly. Two types of commercial catalysts currently being used for ortho- to parahydrogen conversion are: iron(iii) oxide (Fe2O3, IONEX®), and chromium(ii) oxide doped silica catalyst (CrO·SiO2, OXISORB®). We investigate the interaction of ortho- and parahydrogen with the surfaces of these ortho-para conversion catalysts using neutron vibrational spectroscopy. The catalytic surfaces have been characterized using X-ray absorption fine structure (XAFS) and X-ray/neutron pair distribution function measurements.

Original languageEnglish
Pages (from-to)17281-17293
Number of pages13
JournalPhysical Chemistry Chemical Physics
Volume18
Issue number26
DOIs
Publication statusPublished - 2016 May 5

Subject classification (UKÄ)

  • Physical Chemistry

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