Development of MgFe₂O₄ as an oxygen carrier material for chemical looping hydrogen production

Chemical looping hydrogen production (CLHP) is an attractive technology for H₂ production due to its ability to produce H₂ and capture CO₂ from fossil fuels simultaneously. In this paper, we present MgFe₂O₄ as an oxygen carrier material with high efficiency, low cost, and stable properties for CLHP. The redox reactions occurred reversibly in the fuel, steam, and air reactor as MgFe₂O₄→MgO/Fe, MgO/Fe→MgO/Fe₃O₄, and MgO/Fe₃O₄→MgFe₂O₄, respectively. The oxygen transfer capacities of MgFe₂O₄ for 5% H₂/N₂ and 5% CO/N₂ gases were about 23 wt% at 900 °C. Both the oxygen transfer capacity and rate were well maintained during 10 redox cycles at 900 °C. No phase changes or agglomeration occurred as the redox cycle number increased. Similarly, MgFe₂O₄ did not exhibit significant degradation in its total amount or maximum rate of H₂ production during four redox cycles. The average calculated amount of H₂ production for MgFe₂O₄ was 2,806 L/day per unit mass (kg).