Effect of Supports on the Redox Performance of NiFe2O4 in a Chemical Looping Process

NiFe2O4 oxygen carrier (OC) presents higher oxygen carrying capacity than single metal oxides (NiO and Fe2O3). However, the redox ability of NiFe2O4 gets deactivated due to phase segregation. Herein, the investigation of the effect of supports (CeO2, CeZrO2, and ZrO2) on the phase stability and the redox performance of NiFe2O4 during the chemical looping (CL) process are presented. The structure of NiFe2O4-based OCs is characterized using different characterization methods. The CL reaction is conducted in a fixed-bed reactor at 900 degrees C under alternate 5% CO/N-2 and 5% O-2/N-2 atmospheres. The results indicate that the redox performance and the phase stability of NiFe2O4-based OCs are significantly affected by the supports. According to experimental results, CeO2 can improve the oxygen mobility of NiFe2O4. The CeO2-NiFe2O4 OC has the best performance in terms of both recyclability and phase stability during the redox cycles. The results show that CeO2-NiFe2O4 can reduce the tendency of Fe segregation due to the high concentration of oxygen vacancies. It can be reduced and reoxidized to the original crystalline phase of NiFe2O4. Nevertheless, the CeZrO2-NiFe2O4 and ZrO2-NiFe2O4 OCs have drawbacks related to serious sintering and phase segregation into Fe2O3.