Energy-Efficient Cascade Synthesis of Ammonia from Air via Spark Plasma-Mediated Nitrite Generation and CuRu...

Plasma-electrocatalytic cascade ammonia synthesis offers a promising route for decentralized nitrogen fixation, yet remains hindered by excessive NO₃ ^- formation and poor energy matching between the two stages. Here, we propose a strategy that breaks this bottleneck by selectively generating NO₂ ^- via spark-discharge plasma and efficiently reducing it over a CuRu₀.₅ nanoalloy. Systematic optimization of the plasma discharge and electrocatalytic interface enables synergistic energy matching, delivering a record-low specific energy consumption of 273.41 kWh/kg NH₃. Mechanistic studies reveal that Ru modulates the electronic structure of Cu, enhancing NO₂ ^- adsorption and deoxygenation while suppressing the hydrogen evolution reaction. This work establishes a generalized paradigm for low-energy, high-selectivity ammonia synthesis from air and water.