CeO2-confined Ni-Fe alloy enhanced high-temperature CO2 hydrogenation to CO

NiFe2O4 exhibits excellent redox properties and is widely applied in catalytic reactions. However, rapid inactivation under reaction conditions limited its industrial applications. In this study, CeO2-NiFe2O4 composite catalysts were synthesized, and the Reverse Water Gas Shift (RWGS) reaction was measured to reveal its CO2 hydrogenation performance under a high-temperature condition. NiFe2O4 catalysts got deactivated after being reduced to Fe-Ni alloy at 700 degrees C, decreasing the CO2 conversion rate. CeO2 addition can significantly improve its high-temperature activity, and 20CeO2-NiFe2O4 exhibited the best catalytic activity (80.85 %, 700 degrees C). The CeO2-confined maintained Ni-Fe alloy with a relatively small crystal size and larger specific surface area, supporting more active sites for CO2 hydrogenation. CeO2 addition induced higher oxygen vacancy concentration, enhancing CO2 activation and formates species formed on 20CeO2-NiFe2O4, resulting in higher CO2 conversion activity. In addition, 20CeO2-NiFe2O4 maintained its catalytic stability for 50 h at 700 degrees C. The CeO2 confined enhanced the high-temperature stability of Fe-Ni alloy. CeO2 and formed CeFeO3 dispersed in 20CeO2-NiFe2O4 inhibited excessive aggregation of Fe-Ni alloy, and CeO2 inhibited carbon deposition on Fe-Ni alloy, improving Fe-Ni alloy's reaction stability under RWGS reaction conditions. CeO2 confined may give insight into improving metal stability under high-temperature and reductive conditions in heterogeneous catalysis.