Imperial College London
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Prof. Ifan E. L. Stephens

Faculty of Engineering, Department of Materials

Professor in Electrochemistry
 
 
 
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Contact

 

+44 (0)20 7594 9523i.stephens Website

 
 
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Location

 

Molecular Sciences Research HubWhite City Campus

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Summary

 

Publications

Citation

BibTex format

@article{Andersen:2019:10.1038/s41586-019-1260-x,
author = {Andersen, SZ and Colic, V and Yang, S and Schwalbe, JA and Nielander, AC and McEnaney, JM and Enemark-Rasmussen, K and Baker, JG and Singh, AR and Rohr, BA and Statt, MJ and Blair, SJ and Mezzavilla, S and Kibsgaard, J and Vesborg, PCK and Cargnello, M and Bent, SF and Jaramillo, TF and Stephens, IEL and Norskov, JK and Chorkendorff, I},
doi = {10.1038/s41586-019-1260-x},
journal = {Nature},
pages = {504--508},
title = {A rigorous electrochemical ammonia synthesis protocol with quantitative isotope measurements},
url = {http://dx.doi.org/10.1038/s41586-019-1260-x},
volume = {570},
year = {2019}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The electrochemical synthesis of ammonia from nitrogen under mild conditions using renewable electricity is an attractive alternative to the energy-intensive Haber–Bosch process, which dominates industrial ammonia production. However, there are considerable scientific and technical challenges facing the electrochemical alternative, and most experimental studies reported so far have achieved only low selectivities and conversions. The amount of ammonia produced is usually so small that it cannot be firmly attributed to electrochemical nitrogen fixation rather than contamination from ammonia that is either present in air, human breath or ion-conducting membranes, or generated from labile nitrogen-containing compounds (for example, nitrates, amines, nitrites and nitrogen oxides) that are typically present in the nitrogen gas stream, in the atmosphere or even in the catalyst itself. Although these sources of experimental artefacts are beginning to be recognized and managed 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 designed to identify and then eliminate or quantify the sources of contamination. Here we propose a rigorous procedure using 15N2 that enables us to reliably detect and quantify the electrochemical reduction of nitrogen to ammonia. We demonstrate experimentally the importance of various sources of contamination, and show how to remove labile nitrogen-containing compounds from the nitrogen gas as well as 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 find that no ammonia is produced when using the most promising pure-metal catalysts for this reaction in aqueous media, and we successfully confirm and quantify ammonia synthesis using lithium electrodeposition in tetrahydrofuran13. The use
AU  - Andersen,SZ
AU  - Colic,V
AU  - Yang,S
AU  - Schwalbe,JA
AU  - Nielander,AC
AU  - McEnaney,JM
AU  - Enemark-Rasmussen,K
AU  - Baker,JG
AU  - Singh,AR
AU  - Rohr,BA
AU  - Statt,MJ
AU  - Blair,SJ
AU  - Mezzavilla,S
AU  - Kibsgaard,J
AU  - Vesborg,PCK
AU  - Cargnello,M
AU  - Bent,SF
AU  - Jaramillo,TF
AU  - Stephens,IEL
AU  - Norskov,JK
AU  - Chorkendorff,I
DO  - 10.1038/s41586-019-1260-x
EP  - 508
PY  - 2019///
SN  - 0028-0836
SP  - 504
TI  - A rigorous electrochemical ammonia synthesis protocol with quantitative isotope measurements
T2  - Nature
UR  - http://dx.doi.org/10.1038/s41586-019-1260-x
UR  - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000472860000047&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - https://www.nature.com/articles/s41586-019-1260-x
UR  - http://hdl.handle.net/10044/1/72812
VL  - 570
ER  -
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