Sustainable iron-based oxygen carriers for Chemical Looping for Hydrogen Generation

Abstract We report a detailed reactor study of two sustainable Fe-based oxygen carriers (OC) prepared by spray drying. We compare Fe 2 O 3 supported on Al 2 O 3 and MgFeAlO x in isothermal Chemical Looping for Hydrogen Generation. In this process, CH 4 is converted into syngas (H 2  + CO) and H 2 O is used as the oxidant that reduces to pure H 2 . We noticed that the Al 2 O 3 supported OC deactivates quickly while the MgFeAlO x supported OC withstands >60 cycles. We will show that the irreversible formation of an inactive FeAl 2 O 4 phase is responsible for the deactivation of the alumina supported OC. We show detailed information on all the transient stages of the process and the different crystalline forms that are created, and combine this information into a full chemical looping cycle for both OC. Moreover, we evaluate the crushing strength of the oxygen carriers within a full chemical looping cycle and during long-term operation and we investigated the conversion of H 2 O and the selectivity to H 2 -production during long-term oxygen carrier regeneration. The MgFeAlO x support with an extra Fe-based active phase is a promising material to replace the typical Ni-based oxygen carriers, as it forms a sustainable non-toxic, stable and green alternative for hydrogen generation by chemical looping.