Exploration of heterogeneous catalyst for molecular hydrogen ortho-para conversion

Abstract

Molecular hydrogen (H₂) ortho-para conversion (O/P conversion) proceeds slowly at low temperatures accompanying a heat release. Thus, catalysts for accelerating this conversion rate arehighly demanded in termsof the storage andutilizationof liquid H₂. The catalysts for this purpose are experimentally screened by examining a broad range of materials covering magnetic, non-magnetic, metallic, and nonmetallic oxides. The primary conclusions obtained are summarized below. (1) activematerials are required to be non-metallic and to bear the cations with ionic radii smaller than the bond length of H₂. (2) Metallicmaterials have almost no activity irrespective of with or withoutmagnetism (3) The activity of materials belonging to (1) is largely enhanced when the constituting cation has a magnetic moment. In addition, there is a class of materials for which the activity is distinctly enhanced just upon substitution by the foreign ions.

Keywords

catalyst / hydrogen / hydrogen economy / hydrogen liquefaction / ortho-para conversion

RIGHTS & PERMISSIONS

2023 2023 The Authors. Exploration published by Henan University and John Wiley & Sons Australia, Ltd.