Cu-Fe-Al-O mixed spinel oxides as oxygen carrier for chemical looping hydrogen generation

The reduction level for a metal oxides carrier determines the final hydrogen yield for a chemical looping hydrogen generation process. Nevertheless, when the oxygen carrier is reduced at a high level, the sintering of materials would be accelerated. In this paper, we prepare a Cu0.2Fe0.8(FeAl)O-x spinel material and investigate its hydrogen production performance. The results indicate that it exhibits a good redox stability even at reduction level of 0.75 during 20 cycles. In contrast, the deactivation of Fe2O3 oxygen carrier can be obviously observed in the first few cycles. This enable the material with stable hydrogen production at a high yield about 7 mmol/g, which is 3.5 times higher than that of Fe2O3. Upon SEM and XRD characterization techniques, we find that the reason of the both good stability and high hydrogen yield is that the ability of spinel support to inhibit sintering of Cu and Fe active compositions. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.