CeO _{2– x} -Induced Interfacial Reconstruction of Fe ₃ O ₄ /Al ₂ O ₃ for the Formation of Cooperative Fe ⁰ –Fe ₃ O ₄ Dual Sites in Propane Dehydrogenation

Propane dehydrogenation (PDH) is a key process for propylene production, but conventional catalysts are often constrained by high cost, environmental impact, and limited stability under harsh reaction conditions. Fe-based catalysts offer a cost-effective and sustainable alternative due to their intrinsic ability to activate C–H bonds in alkanes. However, precise control over the oxidation state and coordination environment of Fe species to balance PDH activity and stability remains challenging. Herein, we develop a molten-salt-assisted synthesis strategy integrated with CeO 2– x -mediated interfacial engineering to finely tune the structural and electronic properties of Fe species supported on Al 2 O 3 . The molten salt medium enables uniform dispersion and controlled crystallization of Fe 3 O 4, effectively mitigating its over-reduction during high-temperature H 2 treatment. The subsequent incorporation of CeO 2– x modulates the local electronic structure of Fe 3 O 4, inducing a controlled partial reduction to metallic Fe 0 and forming a well-defined Fe 0 –Fe 3 O 4 dual-interface architecture. This interfacial electronic reconstruction enriches the electron density of low-valent Fe sites, facilitating efficient charge transfer during propane activation and promoting rapid propylene desorption. As a result, the optimized catalyst demonstrates accelerated PDH kinetics, high propylene selectivity, and enhanced resistance to coking. This work establishes a scalable route for constructing dual-interface active sites, providing a general design principle for low-cost, high-performance PDH catalysts.