TY - JOUR
T1 - Catalyst-free, highly selective synthesis of ammonia from nitrogen and water by a plasma electrolytic system
AU - Hawtof, Ryan
AU - Ghosh, Souvik
AU - Guarr, Evan
AU - Xu, Cheyan
AU - Sankaran, R. Mohan
AU - Renner, Julie Nicole
N1 - Publisher Copyright:
© 2019 American Association for the Advancement of Science. All rights reserved.
PY - 2019
Y1 - 2019
N2 - There is a growing need for scalable ammonia synthesis at ambient conditions that relies on renewable sources of energy and feedstocks to replace the Haber-Bosch process. Electrically driven approaches are an ideal strategy for the reduction of nitrogen to ammonia but, to date, have suffered from low selectivity associated with the catalyst. Here, we present a hybrid electrolytic system characterized by a gaseous plasma electrode that facilitates the study of ammonia formation in the absence of any material surface. We find record-high faradaic efficiency (up to 100%) for ammonia from nitrogen and water at atmospheric pressure and temperature with this system. Ammonia measurements under varying reaction conditions in combination with scavengers reveal that the unprecedented selectivity is achieved by solvated electrons produced at the plasma-water interface, which react favorably with protons to produce the key hydrogen radical intermediate. Our results demonstrate that limitations in selectivity can be circumvented by using catalyst-free solvated electron chemistry. In the absence of adsorption steps, the importance of controlling proton concentration and transport is also revealed.
AB - There is a growing need for scalable ammonia synthesis at ambient conditions that relies on renewable sources of energy and feedstocks to replace the Haber-Bosch process. Electrically driven approaches are an ideal strategy for the reduction of nitrogen to ammonia but, to date, have suffered from low selectivity associated with the catalyst. Here, we present a hybrid electrolytic system characterized by a gaseous plasma electrode that facilitates the study of ammonia formation in the absence of any material surface. We find record-high faradaic efficiency (up to 100%) for ammonia from nitrogen and water at atmospheric pressure and temperature with this system. Ammonia measurements under varying reaction conditions in combination with scavengers reveal that the unprecedented selectivity is achieved by solvated electrons produced at the plasma-water interface, which react favorably with protons to produce the key hydrogen radical intermediate. Our results demonstrate that limitations in selectivity can be circumvented by using catalyst-free solvated electron chemistry. In the absence of adsorption steps, the importance of controlling proton concentration and transport is also revealed.
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U2 - 10.1126/sciadv.aat5778
DO - 10.1126/sciadv.aat5778
M3 - Article
C2 - 30746439
AN - SCOPUS:85060042472
SN - 0970-7077
VL - 5
JO - Asian Journal of Chemistry
JF - Asian Journal of Chemistry
IS - 1
M1 - eaat5778
ER -