Engineering Inverse CeO_x/Cu Catalysts for High-Yield Plasma Ammonia Synthesis

Plasma-assisted ammonia synthesis offers a low-carbon route compatible with intermittent renewable energy but remains limited by low yields and catalyst instability. Here, we design an inverse oxide-on-metal catalyst (CeO_x/Cu), where CeO_x nanoparticles are uniformly loaded on metallic Cu. The catalyst achieves an ammonia synthesis rate of 6772 μmol g_cat ^-1 h^-1 at 30 W and exhibits excellent long-term stability. Mechanistic studies reveal that oxygen-vacancy-rich CeO_x nanoparticles drive electron transfer toward interfacial Cu sites, constructing highly active Ce-O_x-Cu inverse interfacial centers. This structure strengthens N₂ adsorption and activation, thereby markedly enhancing ammonia synthesis efficiency. This work proposes an oxide-metal interfacial regulation strategy, offering new insights for designing efficient and robust plasma catalysts for ammonia synthesis.