Plasma‐Electrocatalysis Cascade Synthesis of Deuterated Ammonia

Deuterated ammonia (ND3) exhibits growing market demand in the fields of chemical analysis, pharmaceutical industry and semiconductor manufacturing. Currently, industrial production of ND3 relies on harsh conditions and complex processes, leading to high production cost and security risk. Herein, we propose a sustainable relay strategy to produce ND3 by using air and deuterium oxide (D2O) as raw materials, including plasma‐driven air‐to‐NOx conversion and electrocatalytic NOx–‐to‐ND3 conversion. The insufficient supply of reactive deuterium (*D) leads to sluggish kinetics of electrocatalytic deuterium reaction. The well‐designed F modified cobalt (F–Co) catalyst exhibits a remarkable yield of 0.75 mmol h−1 cm−2 and a Faradaic efficiency of 80.43% for ND3 at 200 mA cm−2. The combined results of characterizations reveal that fluorine (F) atom can boost D2O dissociation and suppress competing deuterium evolution reaction, thereby providing abundant *D for deuteration reaction. Notably, a pilot‐scale demonstration system, consisting of non‐thermal plasma, flow electrolyzer, air stripping and ammonia absorber, is constructed to produce practicable ND3 solution (2.8 wt%) with ∼21.45 mmol h−1 ND3 production capability by using air and D2O as sources.