Enhanced ammonia decomposition for hydrogen production over an inverse MgO /Co catalyst

Abstract The development of efficient non‐noble metal catalysts for ammonia decomposition is critical for advancing hydrogen energy technologies. This study presents a breakthrough in catalyst design by constructing an inverse MgO/Co architecture to synergistically enhance both activity and stability. Through systematic comparison with conventional Co/MgO and unsupported Co nanoparticles, the inverse MgO/Co catalyst achieves 98.7% NH 3 conversion at 600°C, with a hydrogen production rate 4.6‐fold higher than Co/MgO at 550°C, alongside exceptional stability at 600°C (>90% retention after 100 h). Advanced characterizations (XRD, TEM, XPS, and TPD) reveal that MgO encapsulation of Co nanoparticles generates abundant interfacial oxygen vacancies and strong metal‐support interactions, which lower the apparent activation energy to 80.2 kJ mol −1 (vs. 172.3 kJ mol −1 for Co/MgO). These interfacial effects optimize NH 3 adsorption energy while facilitating H 2 desorption, as evidenced by NH 3 ‐TPD and isotopic exchange experiments. The inverse structure simultaneously suppresses Co sintering and stabilizes active metallic Co species, addressing the intrinsic trade‐off between activity and durability in conventional catalysts. This work establishes interfacial engineering via inverse design as a universal strategy for high‐performance non‐precious metal catalysts in hydrogen production systems.