Layered Double Hydroxide Derived Mg₂Al-LDO Supported and K-Modified Ru Catalyst for Hydrogen Production via Ammonia Decomposition

Abstract: Mg–Al mixed oxide is derived via the precursor of Mg₂Al-layered double hydroxide (Mg₂Al-LDH), and employed to load Ru and KNO₃ to develop the K–Ru/Mg₂Al-LDO catalyst for hydrogen production through ammonia decomposition. Single MgO and Al₂O₃ were used to prepare reference catalysts K–Ru/MgO and K–Ru/Al₂O₃ for comparison. A mechanically mixed K–Ru/MgO and K–Ru/Al₂O₃ sample was also made to explore the interaction of oxide constituents. K–Ru/Mg₂Al-LDO generally outperforms K–Ru/MgO and K–Ru/Al₂O₃ as well as the Ru-based catalysts supported on other transition metal oxides. The comparison study demonstrated significant impact of structural homogeneity and strong interaction of the oxide constituents on activity. The unique structural feature of Mg₂Al-LDO gives rise to the enhanced surface basicity, low-temperature feasible N₂ desorption, and remarkable hydrogen spillover effect. All these aspects are favorable on K–Ru/Mg₂Al-LDO for electronic modification of Ru sites, rate-determining steps in both low and high reaction temperature, and quick recycle of active sites, accounting for its superior activity plus good durability. Graphical Abstract: [Figure not available: see fulltext.].