A rigorous electrochemical ammonia synthesis protocol with quantitative isotope measurements

Suzanne Zamany Andersen, Viktor Čolić, Sungeun Yang, Jay A. Schwalbe, Adam C. Nielander, Joshua M. McEnaney, Kasper Enemark-Rasmussen, Jon G. Baker, Aayush R. Singh, Brian A. Rohr, Michael J. Statt, Sarah J. Blair, Stefano Mezzavilla, Jakob Kibsgaard, Peter Christian Kjærgaard Vesborg, Matteo Cargnello, Stacey F. Bent, Thomas F. Jaramillo, Ifan E. L. Stephens, Jens K. Nørskov & 1 others Ib Chorkendorff*

*Corresponding author for this work

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Abstract

The electrochemical synthesis of ammonia from nitrogen under mild conditions and using renewable electricity is in principle an attractive alternative1-4 to the demanding, energy-intense Haber-Bosch process, which dominates industrial ammonia production. However, the electrochemical alternative faces considerable scientific and technical challenges5,6 and most experimental studies reported thus far achieve only low selectivities and conversions. In fact, the amount of ammonia produced is usually so small that it is difficult to firmly attribute it to electrochemical nitrogen fixation7-9 and exclude contamination due to ammonia that is either present in air, human breath or ion-conducting membranes9, or generated from labile nitrogen-containing compounds (for example, nitrates, amines, nitrites and nitrogen oxides) that are typically present in the nitrogen gas stream10, in the atmosphere or even the catalyst itself. Although these many and varied sources of potential experimental artefacts are beginning to be recognized and dealt with11,12, concerted efforts to develop effective electrochemical nitrogen reduction processes would benefit from benchmarking protocols for the reaction and from a standardized set of control experiments to identify and then eliminate or quantify contamination sources. Here we put forward such a rigorous procedure that, by making essential use of 15N2, allows us to reliably detect and quantify the electroreduction of N2 to NH3. We demonstrate experimentally the significance of various sources of contamination and show how to remove labile nitrogen-containing compounds present in the N2 gas and how to perform quantitative isotope measurements with cycling of 15N2 gas to reduce both contamination and the cost of isotope measurements. Following this protocol, we obtain negative results when using the most promising pure metal catalysts in aqueous media, and successfully confirm and quantify ammonia synthesis using lithium electrodeposition in tetrahydrofuran13.
Original languageEnglish
JournalNature
Volume570
Pages (from-to)504-508
Number of pages5
ISSN0028-0836
DOIs
Publication statusPublished - 2019

Cite this

Andersen, Suzanne Zamany ; Čolić, Viktor ; Yang, Sungeun ; Schwalbe, Jay A. ; Nielander, Adam C. ; McEnaney, Joshua M. ; Enemark-Rasmussen, Kasper ; Baker, Jon G. ; Singh, Aayush R. ; Rohr, Brian A. ; Statt, Michael J. ; Blair, Sarah J. ; Mezzavilla, Stefano ; Kibsgaard, Jakob ; Vesborg, Peter Christian Kjærgaard ; Cargnello, Matteo ; Bent, Stacey F. ; Jaramillo, Thomas F. ; Stephens, Ifan E. L. ; Nørskov, Jens K. ; Chorkendorff, Ib. / A rigorous electrochemical ammonia synthesis protocol with quantitative isotope measurements. In: Nature. 2019 ; Vol. 570. pp. 504-508.
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title = "A rigorous electrochemical ammonia synthesis protocol with quantitative isotope measurements",
abstract = "The electrochemical synthesis of ammonia from nitrogen under mild conditions and using renewable electricity is in principle an attractive alternative1-4 to the demanding, energy-intense Haber-Bosch process, which dominates industrial ammonia production. However, the electrochemical alternative faces considerable scientific and technical challenges5,6 and most experimental studies reported thus far achieve only low selectivities and conversions. In fact, the amount of ammonia produced is usually so small that it is difficult to firmly attribute it to electrochemical nitrogen fixation7-9 and exclude contamination due to ammonia that is either present in air, human breath or ion-conducting membranes9, or generated from labile nitrogen-containing compounds (for example, nitrates, amines, nitrites and nitrogen oxides) that are typically present in the nitrogen gas stream10, in the atmosphere or even the catalyst itself. Although these many and varied sources of potential experimental artefacts are beginning to be recognized and dealt with11,12, concerted efforts to develop effective electrochemical nitrogen reduction processes would benefit from benchmarking protocols for the reaction and from a standardized set of control experiments to identify and then eliminate or quantify contamination sources. Here we put forward such a rigorous procedure that, by making essential use of 15N2, allows us to reliably detect and quantify the electroreduction of N2 to NH3. We demonstrate experimentally the significance of various sources of contamination and show how to remove labile nitrogen-containing compounds present in the N2 gas and how to perform quantitative isotope measurements with cycling of 15N2 gas to reduce both contamination and the cost of isotope measurements. Following this protocol, we obtain negative results when using the most promising pure metal catalysts in aqueous media, and successfully confirm and quantify ammonia synthesis using lithium electrodeposition in tetrahydrofuran13.",
author = "Andersen, {Suzanne Zamany} and Viktor Čolić and Sungeun Yang and Schwalbe, {Jay A.} and Nielander, {Adam C.} and McEnaney, {Joshua M.} and Kasper Enemark-Rasmussen and Baker, {Jon G.} and Singh, {Aayush R.} and Rohr, {Brian A.} and Statt, {Michael J.} and Blair, {Sarah J.} and Stefano Mezzavilla and Jakob Kibsgaard and Vesborg, {Peter Christian Kj{\ae}rgaard} and Matteo Cargnello and Bent, {Stacey F.} and Jaramillo, {Thomas F.} and Stephens, {Ifan E. L.} and N{\o}rskov, {Jens K.} and Ib Chorkendorff",
year = "2019",
doi = "10.1038/s41586-019-1260-x",
language = "English",
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pages = "504--508",
journal = "Nature",
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Andersen, SZ, Čolić, V, Yang, S, Schwalbe, JA, Nielander, AC, McEnaney, JM, Enemark-Rasmussen, K, Baker, JG, Singh, AR, Rohr, BA, Statt, MJ, Blair, SJ, Mezzavilla, S, Kibsgaard, J, Vesborg, PCK, Cargnello, M, Bent, SF, Jaramillo, TF, Stephens, IEL, Nørskov, JK & Chorkendorff, I 2019, 'A rigorous electrochemical ammonia synthesis protocol with quantitative isotope measurements', Nature, vol. 570, pp. 504-508. https://doi.org/10.1038/s41586-019-1260-x

A rigorous electrochemical ammonia synthesis protocol with quantitative isotope measurements. / Andersen, Suzanne Zamany; Čolić, Viktor; Yang, Sungeun; Schwalbe, Jay A.; Nielander, Adam C.; McEnaney, Joshua M.; Enemark-Rasmussen, Kasper; Baker, Jon G.; Singh, Aayush R.; Rohr, Brian A.; Statt, Michael J.; Blair, Sarah J.; Mezzavilla, Stefano; Kibsgaard, Jakob; Vesborg, Peter Christian Kjærgaard; Cargnello, Matteo; Bent, Stacey F.; Jaramillo, Thomas F.; Stephens, Ifan E. L.; Nørskov, Jens K.; Chorkendorff, Ib.

In: Nature, Vol. 570, 2019, p. 504-508.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - A rigorous electrochemical ammonia synthesis protocol with quantitative isotope measurements

AU - Andersen, Suzanne Zamany

AU - Čolić, Viktor

AU - Yang, Sungeun

AU - Schwalbe, Jay A.

AU - Nielander, Adam C.

AU - McEnaney, Joshua M.

AU - Enemark-Rasmussen, Kasper

AU - Baker, Jon G.

AU - Singh, Aayush R.

AU - Rohr, Brian A.

AU - Statt, Michael J.

AU - Blair, Sarah J.

AU - Mezzavilla, Stefano

AU - Kibsgaard, Jakob

AU - Vesborg, Peter Christian Kjærgaard

AU - Cargnello, Matteo

AU - Bent, Stacey F.

AU - Jaramillo, Thomas F.

AU - Stephens, Ifan E. L.

AU - Nørskov, Jens K.

AU - Chorkendorff, Ib

PY - 2019

Y1 - 2019

N2 - The electrochemical synthesis of ammonia from nitrogen under mild conditions and using renewable electricity is in principle an attractive alternative1-4 to the demanding, energy-intense Haber-Bosch process, which dominates industrial ammonia production. However, the electrochemical alternative faces considerable scientific and technical challenges5,6 and most experimental studies reported thus far achieve only low selectivities and conversions. In fact, the amount of ammonia produced is usually so small that it is difficult to firmly attribute it to electrochemical nitrogen fixation7-9 and exclude contamination due to ammonia that is either present in air, human breath or ion-conducting membranes9, or generated from labile nitrogen-containing compounds (for example, nitrates, amines, nitrites and nitrogen oxides) that are typically present in the nitrogen gas stream10, in the atmosphere or even the catalyst itself. Although these many and varied sources of potential experimental artefacts are beginning to be recognized and dealt with11,12, concerted efforts to develop effective electrochemical nitrogen reduction processes would benefit from benchmarking protocols for the reaction and from a standardized set of control experiments to identify and then eliminate or quantify contamination sources. Here we put forward such a rigorous procedure that, by making essential use of 15N2, allows us to reliably detect and quantify the electroreduction of N2 to NH3. We demonstrate experimentally the significance of various sources of contamination and show how to remove labile nitrogen-containing compounds present in the N2 gas and how to perform quantitative isotope measurements with cycling of 15N2 gas to reduce both contamination and the cost of isotope measurements. Following this protocol, we obtain negative results when using the most promising pure metal catalysts in aqueous media, and successfully confirm and quantify ammonia synthesis using lithium electrodeposition in tetrahydrofuran13.

AB - The electrochemical synthesis of ammonia from nitrogen under mild conditions and using renewable electricity is in principle an attractive alternative1-4 to the demanding, energy-intense Haber-Bosch process, which dominates industrial ammonia production. However, the electrochemical alternative faces considerable scientific and technical challenges5,6 and most experimental studies reported thus far achieve only low selectivities and conversions. In fact, the amount of ammonia produced is usually so small that it is difficult to firmly attribute it to electrochemical nitrogen fixation7-9 and exclude contamination due to ammonia that is either present in air, human breath or ion-conducting membranes9, or generated from labile nitrogen-containing compounds (for example, nitrates, amines, nitrites and nitrogen oxides) that are typically present in the nitrogen gas stream10, in the atmosphere or even the catalyst itself. Although these many and varied sources of potential experimental artefacts are beginning to be recognized and dealt with11,12, concerted efforts to develop effective electrochemical nitrogen reduction processes would benefit from benchmarking protocols for the reaction and from a standardized set of control experiments to identify and then eliminate or quantify contamination sources. Here we put forward such a rigorous procedure that, by making essential use of 15N2, allows us to reliably detect and quantify the electroreduction of N2 to NH3. We demonstrate experimentally the significance of various sources of contamination and show how to remove labile nitrogen-containing compounds present in the N2 gas and how to perform quantitative isotope measurements with cycling of 15N2 gas to reduce both contamination and the cost of isotope measurements. Following this protocol, we obtain negative results when using the most promising pure metal catalysts in aqueous media, and successfully confirm and quantify ammonia synthesis using lithium electrodeposition in tetrahydrofuran13.

U2 - 10.1038/s41586-019-1260-x

DO - 10.1038/s41586-019-1260-x

M3 - Journal article

VL - 570

SP - 504

EP - 508

JO - Nature

JF - Nature

SN - 0028-0836

ER -