Enhanced hydrogen spillover effect in low-temperature ammonia decomposition via N-coordination and O-vacancy-activated Co/La_xCe_{1-x}AlO_{3-y}N_z catalyst
Ammonia decomposition is a key process for generating COx-free hydrogen, yet conventional cobalt catalysts require high temperatures (>550 °C) to overcome the strong Co–N binding that limits N2 desorption. Here we report a novel Co catalyst supported on a Ce and N co-modified perovskite (Co@La_xCe_{1-x}AlO_{3-y}N_z) that achieves 92.6% ammonia conversion with a hydrogen production rate of 9.7 mmol g−1 min−1 at 425 °C and GHSV = 9000 mL h−1 g_cat−1, representing a 125 °C reduction in operating temperature relative to conventional Co-based catalysts. Mechanistic studies using isotopic labeling and in-situ DRIFTS reveal that synergistic Ce and N modification creates a unique LA-L(A+B)-LB active site configuration, which lowers the Schottky barrier at the metal-support interface and promotes facile hydrogen spillover. The reaction proceeds via an interfacial Mars-van Krevelen mechanism, contrasting with the traditional Langmuir-Hinshelwood pathway on conventional Co catalysts. This work provides new insights for designing low-temperature Co-based ammonia decomposition catalysts.