Enhancement of redox properties of iron oxide through metal modification in catalyst assisted chemical looping

Abstract

The focus of this work is to investigate the behavior of bifunctional materials in catalyst assisted chemical looping process. Different ferrite (CoFe2O4 and NiFe2O4) materials modified by CeZrO2 were synthesized via co-precipitation method. Characterization was performed by several analytical techniques such as in-situ XRD, B.E.T., TEM-EDX, etc. The redox activity and stability at different temperatures (500oC and 750oC) were studied in order to determine the most stable bifunctional material. The chemical looping reforming was carried out in two stages, in the first step the bifunctional material was reduced by CH3OH or C2H5OH. In the second step H2O or CO2 were used for regeneration of to study the production of high purity H2 and CO. Addition of CeZrO2 improved the redox behavior of ferrite materials. Among the modified ferrite materials CoFe2O4 were the best performing materials as they could reduce and reoxidize to the as prepared state. The most stable material was 20wt%CoFe2O4-CeZrO2 during methanol and ethanol chemical looping. NiFe2O4 supported materials suffered from deactivation due to phase transformation as they could not cycle back to spinel (NiFe2O4) phase.