La-induced stabilization of Fe-Ni active phases in NiFe2O4 via in situ LaFeO3 formation for efficient CO2 hydrogenation to CO

Abstract

Catalytic hydrogenation of CO 2 to CO via the reverse water-gas shift (RWGS) reaction provides an attractive route for renewable hydrogen utilization and carbon recycling. NiFe 2 O 4 spinels are promising RWGS catalysts owing to abundant oxygen vacancies and excellent CO 2 activation capability. However, the reconstruction-induced aggregation of Fe-Ni active phases under reaction conditions severely limits durability. Herein, La modification regulates phase reconstruction, surface basicity, and oxygen environments. La-induced electron transfer promotes Ni reduction, modifies Fe-O coordination, and enriches defect-related and adsorbed oxygen species, enhancing CO 2 activation. Meanwhile, LaFeO 3 anchors Fe-Ni nanocrystals and suppresses FeO accumulation and sintering. Consequently, 20La 2 O 3 -NiFe 2 O 4 achieves 73.0% CO 2 conversion at 700 °C, and 2.33 times that of pristine NiFe 2 O 4 , while retaining approximately 97% of its initial conversion after 30 h. This work provides an effective strategy for active-phase stabilization, advancing the development of durable catalysts for efficient CO 2 hydrogenation.