Editing Ammonia (section)

=== Electrochemical ===
The [[electrochemical]] synthesis of ammonia involves the reductive formation of [[lithium nitride]], which can be [[protonated]] to ammonia, given a [[proton]] source. The first use of this chemistry was reported in 1930, where lithium solutions in ethanol were used to produce ammonia at pressures of up to 1000&nbsp;bar, with ethanol acting as the proton source.<ref>{{Cite journal |last1=Fichter |first1=Fr. |last2=Girard |first2=Pierre |last3=Erlenmeyer |first3=Hans |date=1930-12-01 |title=Elektrolytische Bindung von komprimiertem Stickstoff bei gewöhnlicher Temperatur |url=https://onlinelibrary.wiley.com/doi/10.1002/hlca.19300130604 |journal=Helvetica Chimica Acta |language=en |volume=13 |issue=6 |pages=1228–1236 |doi=10.1002/hlca.19300130604}}</ref> Beyond simply mediating proton transfer to the nitrogen reduction reaction, ethanol has been found to play a multifaceted role, influencing electrolyte transformations and contributing to the formation of the solid electrolyte interphase, which enhances overall reaction efficiency.<ref>{{Cite journal |last1=Bjarke Valbæk Mygind |first1=Jon |last2=Pedersen |first2=Jakob B. |last3=Li |first3=Katja |last4=Deissler |first4=Niklas H. |last5=Saccoccio |first5=Mattia |last6=Fu |first6=Xianbiao |last7=Li |first7=Shaofeng |last8=Sažinas |first8=Rokas |last9=Andersen |first9=Suzanne Z. |last10=Enemark-Rasmussen |first10=Kasper |last11=Vesborg |first11=Peter C. K. |last12=Doganli-Kibsgaard |first12=Jakob |last13=Chorkendorff |first13=Ib |date=2023-11-22 |title=Is Ethanol Essential for the Lithium-Mediated Nitrogen Reduction Reaction? |journal=ChemSusChem |language=en |volume=16 |issue=22 |pages=e202301011 |doi=10.1002/cssc.202301011 |pmid=37681646 |bibcode=2023ChSCh..16E1011B |issn=1864-5631|doi-access=free }}</ref><ref name="Lazouski-2019" /> 

In 1994, Tsuneto et al. used lithium electrodeposition in [[tetrahydrofuran]] to synthesize ammonia at more moderate pressures with reasonable [[Faradaic efficiency]].<ref>{{Cite journal |last1=Tsuneto |first1=Akira |last2=Kudo |first2=Akihiko |last3=Sakata |first3=Tadayoshi |date=1994-03-04 |title=Lithium-mediated electrochemical reduction of high pressure N2 to NH3 |url=https://dx.doi.org/10.1016/0022-0728%2893%2903025-K |journal=Journal of Electroanalytical Chemistry |language=en |volume=367 |issue=1 |pages=183–188 |doi=10.1016/0022-0728(93)03025-K |issn=1572-6657}}</ref> Subsequent studies have further explored the ethanol–tetrahydrofuran system for electrochemical ammonia synthesis.<ref name="Lazouski-2019">{{Cite journal |last1=Lazouski |first1=Nikifar |last2=Schiffer |first2=Zachary J. |last3=Williams |first3=Kindle |last4=Manthiram |first4=Karthish |date=2019-04-17 |title=Understanding Continuous Lithium-Mediated Electrochemical Nitrogen Reduction |journal=Joule |language=en |volume=3 |issue=4 |pages=1127–1139 |bibcode=2019Joule...3.1127L |doi=10.1016/j.joule.2019.02.003 |issn=2542-4351 |s2cid=107985507 |doi-access=free}}</ref><ref>{{Cite journal |last1=Andersen |first1=Suzanne Z. |last2=Čolić |first2=Viktor |last3=Yang |first3=Sungeun |last4=Schwalbe |first4=Jay A. |last5=Nielander |first5=Adam C. |last6=McEnaney |first6=Joshua M. |last7=Enemark-Rasmussen |first7=Kasper |last8=Baker |first8=Jon G. |last9=Singh |first9=Aayush R. |last10=Rohr |first10=Brian A. |last11=Statt |first11=Michael J. |date=June 2019 |title=A rigorous electrochemical ammonia synthesis protocol with quantitative isotope measurements |url=https://www.nature.com/articles/s41586-019-1260-x |journal=Nature |language=en |volume=570 |issue=7762 |pages=504–508 |bibcode=2019Natur.570..504A |doi=10.1038/s41586-019-1260-x |issn=1476-4687 |pmid=31117118 |s2cid=162182383 |hdl-access=free |hdl=10044/1/72812}}</ref>

In 2020, a solvent-agnostic [[gas diffusion electrode]] was shown to improve nitrogen transport to the reactive lithium. {{chem2|NH3}} production rates of up to {{nobreak|30 ± 5 nmol/(s⋅cm<sup>2</sup>)}} and Faradaic efficiencies of up to 47.5 ± 4% at ambient temperature and 1&nbsp;bar pressure were achieved.<ref>{{Cite journal |last1=Lazouski |first1=Nikifar |last2=Chung |first2=Minju |last3=Williams |first3=Kindle |last4=Gala |first4=Michal L. |last5=Manthiram |first5=Karthish |date=2020-05-01 |title=Non-aqueous gas diffusion electrodes for rapid ammonia synthesis from nitrogen and water-splitting-derived hydrogen |url=https://www.nature.com/articles/s41929-020-0455-8 |journal=Nature Catalysis |language=en |volume=3 |issue=5 |pages=463–469 |doi=10.1038/s41929-020-0455-8 |s2cid=218495730 |issn=2520-1158}}</ref>

In 2021, it was demonstrated that ethanol could be replaced with a tetraalkyl [[phosphonium salt]].<ref name="Suryanto-2021">{{Cite journal|last1=Suryanto|first1=Bryan H. R.|last2=Matuszek|first2=Karolina|last3=Choi|first3=Jaecheol|last4=Hodgetts|first4=Rebecca Y.|last5=Du|first5=Hoang-Long|last6=Bakker|first6=Jacinta M.|last7=Kang|first7=Colin S. M.|last8=Cherepanov|first8=Pavel V.|last9=Simonov|first9=Alexandr N.|last10=MacFarlane|first10=Douglas R.|date=2021-06-11|title=Nitrogen reduction to ammonia at high efficiency and rates based on a phosphonium proton shuttle|url=https://www.science.org/doi/10.1126/science.abg2371|url-access=registration|journal=Science|language=en|volume=372|issue=6547|pages=1187–1191|doi=10.1126/science.abg2371|issn=0036-8075|pmid=34112690|bibcode=2021Sci...372.1187S|s2cid=235396282}}</ref> The study observed {{chem2|NH3}} production rates of {{nobreak|53 ± 1 nmol/(s⋅cm<sup>2</sup>)}} at 69 ± 1% Faradaic efficiency experiments under 0.5&nbsp;bar hydrogen and 19.5&nbsp;bar nitrogen [[partial pressure]] at ambient temperature.<ref name="Suryanto-2021"/> Technology based on this electrochemistry is being developed for commercial fertiliser and fuel production.<ref>{{Cite web|last=Lavars|first=Nick|date=2021-11-30|title=Green ammonia electrolysis breakthrough could finally kill Haber–Bosch|url=https://newatlas.com/energy/green-ammonia-phosphonium-production/|url-status=live|access-date=2021-12-03|website=New Atlas|language=en-US|archive-url=https://web.archive.org/web/20211130072137/https://newatlas.com/energy/green-ammonia-phosphonium-production/ |archive-date=30 November 2021 }}</ref><ref>{{Cite web|last=Blaine|first=Loz|date=2021-11-19|title=FuelPositive promises green ammonia at 60% the cost of today's gray|url=https://newatlas.com/energy/fuelpositive-green-ammonia/|url-status=live|access-date=2021-12-03|website=New Atlas|language=en-US|archive-url=https://web.archive.org/web/20211119060353/https://newatlas.com/energy/fuelpositive-green-ammonia/ |archive-date=19 November 2021 }}</ref>

In 2022, ammonia was produced via the lithium mediated process in a continuous-flow electrolyzer also demonstrating the hydrogen gas as proton source. The study synthesized ammonia at 61 ± 1% Faradaic efficiency at a current density of −6 mA/cm<sup>2</sup> at 1&nbsp;bar and room temperature.<ref name="Fu-2022">{{Cite journal| last1=Fu|first1=Xianbiao| last2=Pedersen|first2=Jakob B.| last3=Zhou|first3=Yuanyuan| last4=Saccoccio|first4=Mattia| last5=Li|first5=Shaofeng| last6=Sažinas|first6=Rokas| last7=Li|first7=Katja| last8=Andersen|first8=Suzanne Z.| last9=Xu|first9=Aoni| last10=Deissler|first10=Niklas H.| last11=Mygind|first11=Jon Bjarke Valbæk| last12=Wei|first12=Chao| last13=Kibsgaard|first13=Jakob| last14=Vesborg|first14=Peter C. K.| last15=Nørskov|first15=Jens K.| last16=Chorkendorff|first16=Ib| date=2022-02-16|title=Continuous-flow electrosynthesis of ammonia by nitrogen reduction and hydrogen oxidation|url=https://www.science.org/doi/10.1126/science.adf4403|journal=Science|language=en|volume=379|issue=6633|pages=707–712|doi=10.1126/science.adf4403|issn=|pmid=36795804|bibcode=|s2cid=}}</ref>