Catalyst-free, highly selective synthesis of ammonia from nitrogen and water by a plasma electrolytic system

Ryan Hawtof, Souvik Ghosh, Evan Guarr, Cheyan Xu, R. Mohan Sankaran, Julie Nicole Renner

Research output: Contribution to journalArticle

Abstract

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.

Original languageEnglish (US)
Article numbereaat5778
JournalAsian Journal of Chemistry
Volume31
Issue number2
DOIs
StatePublished - Jan 1 2019

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Ammonia
Nitrogen
Plasmas
Catalysts
Water
Catalyst selectivity
Protons
Atmospheric temperature
Electrons
Feedstocks
Atmospheric pressure
Hydrogen
Adsorption
Electrodes

PubMed: MeSH publication types

  • Journal Article

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Catalyst-free, highly selective synthesis of ammonia from nitrogen and water by a plasma electrolytic system. / Hawtof, Ryan; Ghosh, Souvik; Guarr, Evan; Xu, Cheyan; Sankaran, R. Mohan; Renner, Julie Nicole.

In: Asian Journal of Chemistry, Vol. 31, No. 2, eaat5778, 01.01.2019.

Research output: Contribution to journalArticle

Hawtof, Ryan ; Ghosh, Souvik ; Guarr, Evan ; Xu, Cheyan ; Sankaran, R. Mohan ; Renner, Julie Nicole. / Catalyst-free, highly selective synthesis of ammonia from nitrogen and water by a plasma electrolytic system. In: Asian Journal of Chemistry. 2019 ; Vol. 31, No. 2.
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