Mn-Fe-Al-O mixed spinel oxides as oxygen carrier for chemical looping hydrogen production with CO2 capture

Preparing the oxygen storage material capable of being highly reduced with desirable stability is important to reduce the solid circling rate in a fluidized bed chemical looping reactor. Nevertheless, the high oxygen carrier reduction degree would accelerate sintering. In this work a Mn0.5Fe0.5(FeAl)O-x material is synthesized as the oxygen carrier of chemical looping hydrogen production process. It exhibits a good redox stability during 30 cycles even operated at reduction degree of 0.8. In fixed bed tests, the Mn0.5Fe0.5(FeAl)O-x material shows a high and stable hydrogen yield of 2.1 mmol/g at 20th cycle, while the CO completely converts to CO2. In contrast, the deactivation can be obviously observed in the case of Fe2O3 oxygen carrier. The hydrogen yield is only 0.44 mmol/g at 20th cycle which is about one fifth of Mn0.5Fe0.5(FeAl)O-x sample.