Strong Metal-Support Interaction-Induced Hydrogen Spillover Boosts Thermocatalytic Ammonia Decomposition

Efficient non-noble-metal catalysts are essential for the industrial application of ammonia decomposition reaction (ADR). This work reports a Ni-Co bimetallic thermocatalyst supported by BaCe_0.8Y_0.2O_3-δ (BCY), a proton-conducting cermet, demonstrating state-of-the-art ADR performance. This catalyst achieves 100% NH₃ conversion at 550 °C with a gas hourly space velocity of 9000 mL h⁻¹ g_cat⁻¹ and 95.1% conversion at 520 °C, notably lowering ADR temperature requirements. It also demonstrates outstanding stability under diverse conditions. The superior ADR activity arises from Ni-Co synergies, Ce's strong basicity, as well as extensive hydrogen spillover facilitated by Y doping-induced high oxygen vacancies. Specifically, BCY's strong adsorption of H* promotes the migration of H* from the active Ni/Co surface to oxygen sites of the support and subsequent rapid diffusion as OH* in oxygen vacancy channels. This metal-support-interaction-induced hydrogen spillover effect further liberates the original active sites and boosts ammonia activation.