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

Summary, in English

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.

• Författare: 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
• Avdelning/ar: European Spallation Source ESS AB; MAX IV-laboratoriet
• Publiceringsår: 2016-05-05
• Språk: Engelska
• Sidor: 17281-17293
• Publikation/Tidskrift/Serie: Physical Chemistry Chemical Physics
• Volym: 18
• Issue: 26
• Länkar: http://dx.doi.org/10.1039/c6cp01154c
• Dokumenttyp: Artikel i tidskrift
• Förlag: Royal Society of Chemistry
• Ämne: Physical Chemistry
• Status: Published
• ISBN/ISSN/Övrigt: ISSN: 1463-9084