Chemical looping hydrogen storage and production: use of binary ferrite-spinel as oxygen carrier materials

Abstract

Chemical looping hydrogen storage and the recovery of iron oxides by the redox cycles were recommended as an emerging approach for large-scale hydrogen storage with a high volumetric hydrogen storage density. However, iron oxides should be operated at a high temperature (>800 °C) for its sufficient redox activity, which would lead to a rapid deterioration of hydrogen storage performance over cycles. In this work, a series of ferrite-spinel materials A_0.25Fe_2.75O₄ (A = Co, Cu, Ni, Zn or Mn) were prepared. Among all the additives to iron oxides, Co_0.25Fe_2.75O₄ exhibits the highest volumetric hydrogen storage density (∼62.47 g L⁻¹) and an average hydrogen production rate (∼132 μmol g⁻¹ min⁻¹) under 550 °C. Besides, the storage capacity was maintained over 10 cycles. The volumetric hydrogen storage density of this material was proportionate to the most advanced Rh–FeO_x containing rare-earth metal; thus, it may have the potential for industrial application.