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

Bowen Lu,Ziqiang Han,Xinyu Zhi,Liqi Zhang

NiFe 2 O 4 exhibits excellent redox properties and is widely applied in catalytic reactions. However, rapid inactivation under reaction conditions limited its industrial applications. In this study, CeO 2 -NiFe 2 O 4 composite catalysts were synthesized, and the Reverse Water Gas Shift (RWGS) reaction was measured to reveal its CO 2 hydrogenation performance under a high-temperature condition. NiFe 2 O 4 catalysts got deactivated after being reduced to Fe-Ni alloy at 700 °C, decreasing the CO 2 conversion rate. CeO 2 addition can significantly improve its high-temperature activity, and 20CeO 2 -NiFe 2 O 4 exhibited the best catalytic activity (80.85 %, 700 °C). The CeO 2 -confined maintained Ni-Fe alloy with a relatively small crystal size and larger specific surface area, supporting more active sites for CO 2 hydrogenation. CeO 2 addition induced higher oxygen vacancy concentration, enhancing CO 2 activation and formates species formed on 20CeO 2 -NiFe 2 O 4 , resulting in higher CO 2 conversion activity. In addition, 20CeO 2 -NiFe 2 O 4 maintained its catalytic stability for 50 h at 700 °C. The CeO 2 confined enhanced the high-temperature stability of Fe-Ni alloy. CeO 2 and formed CeFeO 3 dispersed in 20CeO 2 -NiFe 2 O 4 inhibited excessive aggregation of Fe-Ni alloy, and CeO 2 inhibited carbon deposition on Fe-Ni alloy, improving Fe-Ni alloy’s reaction stability under RWGS reaction conditions. CeO 2 confined may give insight into improving metal stability under high-temperature and reductive conditions in heterogeneous catalysis.