| Solid oxygen carriers are usually used in a chemical looping process to transfer oxygen from the oxygen gaseous to fuel, which can avoid the direct contact of these two reactants and hence decrease the energy penalty of separation. Among the solid oxygen carriers, iron-based oxygen carrier is an attractive option due to its inherent properties of low cost and environmentally-friendly. The research of iron-based oxygen carriers in chemical looping was summarized. Due to the low reduction ability of active iron oxide, it usually is doped with other metals such as alkali metals (Na, K, Ca) and transition metals (Cu, Co, Ni, etc.) for modification. The research of oxygen carriers recently focuses on composite metal oxygen carriers such as perovskite, ferrite, hexaaluminate, CeO2-type oxygen carriers, etc. Among them, the perovskite has excellent oxygen transfer ability, great thermal stability, and high mechanical strength. Substituting with different A/B-sites ions or combining with other materials recently has become a hot topic of perovskite. |
