We have developed a sustainable method to produce NH3directly from air using a plasma tandem-electrocatalysis
system
that operates via the N2–NOx–NH3pathway. To efficiently reduce NO2–to NH3, we propose a novel
electrocatalyst consisting of defective N-doped molybdenum sulfide
nanosheets on vertical graphene arrays (N-MoS2/VGs). We
used a plasma engraving process to form the metallic 1T phase, N doping,
and S vacancies in the electrocatalyst simultaneously. Our system
exhibited a remarkable NH3production rate of 7.3 mg h–1cm–2at −0.53 V vs RHE,
which is almost 100 times higher than the state-of-the-art electrochemical
nitrogen reduction reaction and more than double that of other hybrid
systems. Moreover, a low energy consumption of only 2.4 MJ molNH3–1was achieved in this study.
Density functional theory calculations revealed that S vacancies and
doped N atoms play a dominant role in the selective reduction of NO2–to NH3. This study opens up
new avenues for efficient NH3production using cascade
systems.