Effect of Supports on the Redox Performance of NiFe2O4 in a Chemical Looping Process. Issue 9 (5th June 2019)

• Record Type: Journal Article
• Authors: Ma, Zhong; Zeng, Dewang; Zhang, Shuai; Xiao, Rui
• Is Part Of: Energy technology. Volume 7:Issue 9(2019:Sep.)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-06-05
• Subjects: chemical looping processes -- NiFe2O4 -- oxygen vacancies -- phase segregation -- supports; Energy development -- Periodicals; Power resources -- Periodicals; 333.79
• DOI: 10.1002/ente.201900374
• Languages: English
• ISSNs: 2194-4288

Abstract

Abstract : NiFe2 O4 oxygen carrier (OC) presents higher oxygen carrying capacity than single metal oxides (NiO and Fe2 O3 ). However, the redox ability of NiFe2 O4 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 NiFe2 O4 during the chemical looping (CL) process are presented. The structure of NiFe2 O4 ‐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/N2 and 5% O2 /N2 atmospheres. The results indicate that the redox performance and the phase stability of NiFe2 O4 ‐based OCs are significantly affected by the supports. According to experimental results, CeO2 can improve the oxygen mobility of NiFe2 O4 . The CeO2 –NiFe2 O4 OC has the best performance in terms of both recyclability and phase stability during the redox cycles. The results show that CeO2 –NiFe2 O4 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 NiFe2 O4 . Nevertheless, the CeZrO2 –NiFe2 O4 and ZrO2 –NiFe2 O4 OCs have drawbacks related to serious sintering and phase segregation into Fe2 O3 . Abstract : The redox performance and the phase stability of NiFe2 O4 oxygen carriers are significantly affected by the supports. The obtained results indicate that the high concentration of oxygen vacancies can suppress the phase segregation of the NiFe2 O4 spinel structure. This study provides guidance to produce more improved materials with high reactivity and cyclic stability for chemical looping applications.