Evaluation of multi-cycle performance of chemical looping dry reforming using CO2 as an oxidant with Fe–Ni bimetallic oxides

Chemical looping dry reforming (CLDR) is an innovative technology for CO 2 utilization using the chemical looping principle. The CLDR process consists of three stages, i.e. CH 4 reduction, CO 2 reforming, and air oxidation . Spinel nickel ferrite (NiFe 2 O 4 ) was prepared and its multi-cycle performance as an oxygen carrier for CLDR was experimentally investigated. X-ray diffraction (XRD) and Laser Raman spectroscopy showed that a pure spinel crystalline phase (NiFe 2 O 4 ) was obtained by a parallel flow co-precipitating method. NiFe 2 O 4 was reduced into Fe–Ni alloy and wustite (Fe x O) during the CH 4 reduction process. Subsequent oxidation of the reduced oxygen carrier was performed with CO 2 as an oxidant to form an intermediate state: a mixture of spinel Ni 1− x Fe 2+ x O 4 , Fe 2+ y O 4 and metallic Ni. And CO was generated in parallel during this stage. Approximate 185 mL of CO was generated for 1 g spinel NiFe 2 O 4 in a single cycle. The intermediate oxygen carrier was fully oxidized in the air oxidation stage to form a mixture of Ni 1+ x Fe 2− x O 4 and Fe 2 O 3 . Although the original state of oxygen carrier (NiFe 2 O 4 ) was not fully regenerated and agglomeration was observed, a good recyclability was shown in 10 successive redox cycles.