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

Abstract 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.