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

NiFe 2 O 4 oxygen carrier (OC) presents higher oxygen carrying capacity than single metal oxides (NiO and Fe 2 O 3 ). However, the redox ability of NiFe 2 O 4 gets deactivated due to phase segregation. Herein, the investigation of the effect of supports (CeO 2 , CeZrO 2 , and ZrO 2 ) on the phase stability and the redox performance of NiFe 2 O 4 during the chemical looping (CL) process are presented. The structure of NiFe 2 O 4 -based OCs is characterized using different characterization methods. The CL reaction is conducted in a fixed-bed reactor at 900 °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 NiFe 2 O 4 -based OCs are significantly affected by the supports. According to experimental results, CeO 2 can improve the oxygen mobility of NiFe 2 O 4 . The CeO 2 –NiFe 2 O 4 OC has the best performance in terms of both recyclability and phase stability during the redox cycles. The results show that CeO 2 –NiFe 2 O 4 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 NiFe 2 O 4 . Nevertheless, the CeZrO 2 –NiFe 2 O 4 and ZrO 2 –NiFe 2 O 4 OCs have drawbacks related to serious sintering and phase segregation into Fe 2 O 3 .