Áburður frá lofti og vatni: Frá reikningum til tilrauna - öndvegisverkefni lokið

Fréttatilkynning verkefnisstjóra

6.3.2020

Binding köfnunarefnis á formi ammóníaks og/eða nítrats er gríðalega mikilvægt ferli þar sem þessi efni eru notuð til að búa til köfnunarefnisáburð til að auka uppskeru bænda. Fyrir um 100 árum þróuðu þeir Haber og Bosch ferli sem kennt er við þá þar sem N2 úr andrúmsloftinu (sem er 78%) er hvarfað við H2 gas við háan hita og þrýsting til framleiðslu á ammóníaki, en þessi aðferð olli því að fólksfjöldinn jókst mjög mikið á síðustu öld þar sem fæðuöryggi jókst til muna. Fyrir þessa uppfinningu fengu þeir báðir Nóbelsverðlaunin í efnafræði. Þegar ammóníak hefur verið myndað er hægt að oxa ammóníakið í nítrat með Ostwald ferlinu. Haber-Bosch verksmiðjur eru stórar og staðsettar á fáum stöðum á jörðinni og því þarf að flytja áburðinn langar leiðir. Stærstur hluti verksmiðjanna fer í að búa til vetnisgas frá jarðgasi en það ferli er mjög orkufrekt og óumhverfisvænt þar sem tvö tonn af CO2 eru losuð út í andrúmsloftið fyrir hvert tonn af ammóníaki sem er búið til. Þetta veldur um 1% losun CO2 af mannavöldum en um 2% af allri orkunotkun jarðarbúa fer í þetta ferli. Það er því mjög mikilvægt að þróa ferli sem er umhverfisvænt og sjálfbært en þar lofar rafefnafræði mjög góðu þar sem hægt er að nýta endurnýjanlegan orkugjafa (sól, vind, o.s.frv.) til að knýja ferlið áfram við herbergishita og -þrýsting, en í stað vetnisgass er hægt að nota vatn til að búa til uppleystar róteindir og rafeindir, og eina auka afurðin er súrefnisgas. Með þessari aðferð væri hægt að búa til nituráburð á smáskala þ.a. hver og einn bóndi gæti framleitt eigin áburð á umhverfisvænan hátt, frá lofti, vatni og rafmagni. Á síðustu 2-3 árum hefur opnast nýtt rannsóknarsvið á heimsvísu til að leysa þetta vandamál, en tölvureikningar frá okkar hópi hafa átt stóran þátt í þeim áhuga vísindamanna.

Markmið verkefnisins “Fertilizer from air and water: From theory to experiments” voru í rauninni fjórskipt. Haldið var áfram að leita að heppilegum efnahvötum með tölvureikningunum þar sem þrír flokkar efnahvata voru aðallega teknir fyrir; málmnítríð, málmoxíð og málmsúlfíð. Þrír til fimm efnahvatar voru fundnir í hverjum flokki efnasambanda. Þessir reikningar byggja á nokkrum nálgunum, en við gerðum einnig mun ítarlegri reikninga sem sýna að einföldu reikningarnir gefa nokkuð nákvæma mynd, t.d. hvarfleiðina sem og yfirspennuna sem þarf að nota. Ræktun þessara efnahvata sem þunnar húðir sem passa í mismunandi rafefnafræðilegar cellur voru framkvæmdar, en efnahvatana þurfti einnig að greina bæði fyrir og eftir rafefnafræðilegu tilraunirnar. Síðast en ekki síst þá var tilraunastofa fyrir rafefnafræðilegu tilraunirnar sett upp og aðferðafræði til prófunar hvatanna þróuð. Þetta er mjög vandasamt efnavarf því ammóníak og nitur leynist víða og því þarf að tryggja að mælt ammóníak komi fram vegna efnahvarfs N2 gass en ekki vegna annarra þátta. Í þessu verkefni þróuðum við aðferðafræði sem gefur afgerandi niðurstöður um hvort að um efnahvötun sé að ræða eða ekki.

Þessi aðferðafræði nýtist nú til þess að prófa hratt og örugglega fleiri hvata, með mikilli vissu um gæði niðurstaðnanna. Við væntum þess að birta niðurstöður um hvötun, sem og almennar rafefnafræðilegar niðurstöður um eiginleika prófaðra yfirborða á næstu misserum.

Mörg samstarfsverkefni mynduðust meðan á þessu verkefni stóð. Gott samstarf myndaðist við Grein Research ehf. sem er sprotafyrirtæki staðsett í Háskóla Íslands. Samstarf við ýmsa rannsóknarhópa t.d. í Svíþjóð og Englandi var myndað, þar sem þekking og tækjabúnaður var til staðar en vantaði hérlendis. Þá hélst gott samstarf við bæði dr. Anna Garden á Nýja Sjálandi og dr. Líneyju Árnadóttur í Bandaríkjunum, sem voru meðumsækjendur á þessari umsókn. Einnig var hafið samstarf við dr. Cristina Giordano, sérfræðing við Queen Mary University London. Margar af niðurstöðum þessa verkefnis hafa birst í alþjóðlegum tímaritum, ráðstefnuritum, bókarköflum og einkaleyfum og er listað hér fyrir neðan. Þá voru niðurstöðurnar kynntar víðsvegar um heiminn af þátttakendum verkefnisins. 

Einkaleyfi fyrir notkun málmnítríða, málmoxíða og málmsúlfíða voru send inn og eru komin mislangt í ferlinu. Þar að auki var eitt einkaleyfi sent inn sem tengist rafefnafræðilegu tilraununum þar sem púsluð spenna er notuð. Fyrsta einkaleyfið, sem byggir á notkun málmnítríða sem efnahvata fyrir rafefnafræðilega afoxun niturs í ammóníak, hefur verið samþykkt hérlendis sem og í Bandaríkjunum, Kína, Rússlandi og Ísrael en EPO hefur lýst því yfir að ætla að samþykkja það og við erum í þann mund að velja lönd innan Evrópu sem við viljum fá einkaleyfið samþykkt í. Þá hefur Indland sent álitsgerð, og einkaleyfið er enn í vinnslu í Kanada. Einkaleyfið um málmoxíðin, málmsúlfíð og púlsun hafa verið send inn í PCT ferli.

Eitt yfirborðanna sem falla innan okkar einkaleyfa (NbO2 rutile) hefur verið prófað af öðrum rannsóknarhópi og sýnt hefur verið fram á allt að 32% hvatavirkni þeirra yfirborða, sem er mesta nýtni sem birst hefur hingað til. Þetta yfirborð verður prófað við fleiri nýjar hvarfaðstæður á tilraunastofunni okkar á næstunni. 

Þá stofnuðum við sprotafyrirtækið Atmonia ehf. í kringum þetta verkefni til að taka niðurstöður þessa verkefnis áfram sem vöru á markað en við erum um þessar mundir að leita að fjármagni til að flýta því ferli. Við fórum í gegnum fyrirtækjahraðalinn Startup Energy Reykjavík, unnum Gulleggið 2017 og fengum alþjóðlega viðurkenningu frá Sameinuðu Þjóðunum (UNIDO) vorið 2019.

English:

With this Grant of Excellence, we had the opportunity to hire a number of students and postdocs to work on electrochemical N2 reduction reaction (NRR) to ammonia in aqueous solution at ambient conditions. Before this project started we had worked on a number of computer simulations for this reaction, but here we got the opportunity to set-up an experimental laboratory to test these predicted catalysts. The work was divided into four work-packages; 1) computer simulations, 2) catalyst synthesis, 3) establishing experimental laboratory and developing the methodology and protocols and 4) test the catalyst candidates in electrochemical experiments. 

Fixing nitrogen into ammonia and/or nitrates is an extremely important process because those chemicals are used to make nitrogen fertilizer in order to increase crop yields for farmers. About 100 years ago Haber and Bosch discovered and developed a process named after them where N2 from the atmosphere (which is 78% nitrogen) is reacted with H2 gas at high temperature and high pressure to produce ammonia, but this method is the reason that our population increased considerable on the last century where food security increased accordingly. For this invention they both got the Nobel prize in chemistry. When ammonia has been formed it can be oxidized to nitrate with the Ostwald process. Haber-Bosch chemical plants are very large and placed only at a few places in the world and therefore the fertilizer has to be transported long distances. The largest part of the plant goes into producing hydrogen gas from natural gas or coals but that process is very energy intense and polluting where two tons of CO2 gas is released into the atmosphere for each ton of ammonia that is produced. This process results in around 1% of man-made CO2 emission and around 2% of the global energy consumption is dedicated to this process. It is therefore very important to develop a process that is environmentally friendly and sustainable but there electrochemistry is very promising where renewable energy can be used (such as solar, wind, etc.) to drive the process at ambient temperature and atmospheric pressure. However, instead of using hydrogen gas, water can be used to create solvated protons and electrons, where the only byproduct is oxygen gas. With this technology, nitrogen-fertilizer can be produced at a small-scale where each farmer can produce their own fertilizer in environmentally friendly way from atmosphere, water and electricity. In the last 2-3 years a new research field has opened up world-wide in order to solve this problem but our computer simulations have had a large contribution to spark interests among scientists. 

The work within the project “Fertilizer from air and water: From theory to experiments” was four-fold. Computer simulations were continued to search for catalyst candidates were mainly three classes of materials were considered; metal nitrides, metal oxides and metal sulfides. Three to five promising candidates were found within each classes of materials. These computer calculations used several assumptions, but we also did a much more accurate and detailed calculations that concluded that these simpler simulations give quite accurate predictions regarding e.g. the reaction pathways to different products as well as the overpotential required. Thin film growth of the predicted catalysts was then carried out that fitted into different electrochemical cells, but the composition of the materials was also characterized before and after electrochemical experiments. Last but not least an electrochemical laboratory was established and a methodology and protocols developed to test the candidates in an efficient way. This is a very difficult reaction to accomplish as well as to verify or proof because ammonia and nitrogen exists in trace amount in our surrounding and therefore it needs to be made sure that the measured ammonia is indeed resulting from catalyzing N2 gas but not from other sources. Within this project a methodology was developed that gives robust results whether a catalysis is taking place or not. 

This methodology can now be used to test fast and accurately a range of catalyst candidates with a high confidence on the quality of the results. We anticipate to publish our results on catalysis of NRR as well as general electrochemical results on the characteristics of the tested surfaces in the upcoming months.

Several research collaborations were established during the course of this project. A good collaboration was formed with Grein Research which is a spin-off company located at the University of Iceland. Collaborations with research groups in e.g. Sweden and England was established where know-how and instruments exist which do not exist yet in Iceland. A good collaboration was continued with both Dr. Anna Garden in New Zealand and Dr. Líney Árnadóttur in U.S., but they were both co-applicants on this grant. In addition, we started collaborating with Dr. Cristina Giordano at the Queen Mary University London. Quite a few results from this overall project have been published in international journals, conference proceedings, a book chapter and several patents and these outputs are listed here below. Finally, the results of this project were presented all around the world by the participants in this project.

Patents for using metal nitrides, metal oxides and metal sulfides were submitted and are in a different stage in that patent process. In addition, another patent was submitted that describes the electrochemical experimental procedure through potential pulsing. The first patent that deals with using metal nitrides as catalysts for NRR to ammonia has been approved in Iceland as well as in USA, China, Russia and Israel but EPO has informed us that they will grant it but we are just about deciding in which countries within Europe we want to have that patent granted in. Then India has sent us their report, but the patent is still pending in Canada. The patent on the metal oxides, metal sulfides and our electrochemical pulsing method have been submitted to the PCT process. 

One of our catalyst candidates that are within our patent´s portfolio (NbO2 in a rutile crystal structure) has been tested by another research group and there they measure up to 32% current efficiency which is the highest efficiency that has been published today. This surface is being tested in different and new reaction conditions in our laboratory right now. 

Finally, a spin-off company Atmonia was founded around this activity that aims at taking these results into a product and to the market but we are at the moment looking for investors to finance the next steps in order for accelerating the process. We took part of the business accelerator Startup Energy Reykjavík, won the Golden Egg in 2017 and received an international award from the United Nations (UNIDO) in spring 2019.

Journal publications

26. “Geometric and electronic effects contributing to N2 dissociation barriers on a range of active sites on Ru nanoparticles” C. Casey-Stevens, S. Lambie, C. Ruffman, E. Skúlason & A. Garden 
Journal of Physical Chemistry C (2019) DOI: 10.1021/acs.jpcc.9b09563

25. “Elucidating the mechanism of electrochemical N2 reduction at the Ru(0001) electrode” E. Tayyebi, Y. Abghoui & E. Skúlason
ACS Catalysis, 9 (2019) 11137

24. “Biomimetic nitrogen fixation catalyzed by transition metal sulfide surfaces in an electrolytic cell” Y. Abghoui, S.B. Sigtryggsson & E. Skúlason
ChemSusChem, 12 (2019) 4265

23. “Catalytic trends of nitrogen doped carbon nanotubes for oxygen reduction reaction” P.M. Gíslason & E. Skúlason
Nanoscale, 11 (2019) 18683

22. “Elucidation of temperature-programmed desorption of high-coverage hydrogen on Pt (211), Pt (221), Pt (533) and Pt (553) based on density functional theory calculations” M.J. Kolb, A.L. Garden, C. Badan, J.A.G. Torres, E. Skúlason, L.B.F. Juurlink, H. Jónsson & M.T.M. Koper
Physical Chemistry Chemical Physics, 21 (2019) 17142

21. “Assessment of constant-potential implicit solvation calculations of electrochemical energy barriers for H2 evolution on Pt” M. Van den Bossche, E. Skúlason, C. Rose-Petruck & H. Jónsson  
Journal of Physical Chemistry C, 123 (2019) 4116

20. “57Fe Mössbauer study of epitaxial TiN thin film grown on MgO (1 0 0) by magnetron sputtering” B. Qi, H.P. Gunnlaugsson, A. Mokhles Gerami, H.P. Gislason, S. Ólafsson, F. Magnus, T.E. Mølholt, H. Masenda, A. Tarazaga Martín-Lueugo, A. Bonanni, P.B. Krastev, V. Masondo, I. Unzueta, K. Bharuth-Ram, K. Johnston, D. Naidoo, J. Schell, P. Schaaf, the ISOLDE collaboration
Applied Surface Science, 464 (2019) 682

19. “Electroreduction of CO on Polycrystalline Copper at Low Overpotentials” E. Bertheussen, T.V. Hogg, Y. Abghoui, A.K. Engstfeld, I. Chorkendorff & I.E.L. Stephens 
ACS Energy Letters, 3 (2018) 634 

18. “Calculations of product selectivity in electrochemical CO2 reduction” J. Hussain, H. Jónsson & E. Skúlason 
ACS Catalysis, 8 (2018) 5240

17. “Trends of electrochemical CO2 reduction reaction on transition metal oxide catalysts” E. Tayyebi, J. Hussain, Y. Abghoui & E. Skúlason 
Journal of Physical Chemistry C, 122 (2018) 10078

16. “Quantification of liquid products from the electroreduction of CO2 and CO using static headspace-gas chromatography and nuclear magnetic resonance spectroscopy” E. Bertheussen, Y. Abghoui, Z.P. Jovanov, A.S. Varela, I.E.L. Stephens & I. Chorkendorff 
Catalysis Today, 288 (2017) 54

15. “Hydrogen evolution reaction catalyzed by transition metal nitrides” Y. Abghoui & E. Skúlason 
Journal of Physical Chemistry C, 121 (2017) 24036

14. “Computational screening of rutile oxides for electrochemical ammonia formation” Á.B. Höskuldsson, Y. Abghoui, A.B. Gunnarsdóttir & E. Skúlason 
ACS Sustainable Chemistry & Engineering, 5 (2017) 10327

13. “Atomic scale simulations of heterogeneous electrocatalysis: recent advances” E. Skúlason & H. Jónsson 
Advances in Physics: X, 2 (2017) 481

12. “Computational Predictions of Catalytic Activity of Zincblende (110) Surfaces of Metal Nitrides for Electrochemical Ammonia Synthesis” Y. Abghoui & E. Skúlason
Journal of Physical Chemistry C, 121 (2017) 6141

11. “Electrochemical synthesis of ammonia via Mars-van Krevelen mechanism on the (111) facets of group III–VII transition metal mononitrides” Y. Abghoui & E. Skúlason 
Catalysis Today, 286 (2017) 78

10. “Onset potentials for different reaction mechanisms of nitrogen activation to ammonia on transition metal nitride electro-catalysts” Y. Abghoui & E. Skúlason 
Catalysis Today, 286 (2017) 69

9. "Epitaxial and textured TiN thin films grown on MgO(100) by reactive HiPIMS: the impact of charging on epitaxial to textured growth crossover", S. Shayestehaminzadeh, E.B Thorsteinsson, D. Primetzhofer, F. Magnus & S. Olafsson 
Journal of Physics D: Applied Physics, 49 (2016) 455301

8. “Protection of Si photocathode using TiO2 deposited by high power impulse magnetron sputtering for H2 evolution in alkaline media” D. Bae, S. Shayestehaminzadeh, E. B. Thorsteinsson, T. Pedersen, O. Hansen, B. Seger, P. C. K. Vesborg, S. Olafsson & I. Chorkendorff 
Solar Energy Materials & Solar Cells 144 (2016) 758

7. “Faraday efficiency and mechanism of electrochemical surface reactions: CO2 reduction and H2 formation on Pt(111)” J. Hussain, H. Jónsson & E. Skúlason 
Faraday Discuss. 195 (2016) 619

6. "Electroreduction of N2 to ammonia at ambient conditions on mononitrides of Zr, Nb, Cr, and V – A DFT guide for experiments", Y. Abghoui, A.L. Garden, J. Howalt, T. Vegge & E. Skúlason 
ACS Catalysis, 6 (2016) 635

5. “On the pH dependence of electrochemical proton transfer barriers” J. Rossmeisl, K. Chan, E. Skúlason, M. E. Björketun & V. Tripkovic
Catalysis Today 262 (2016) 36

4. "The mechanism of industrial ammonia synthesis revisited: Calculations of the role of the associative mechanism", A. L. Garden & E. Skúlason 
Journal of Physical Chemistry C 119 (2015) 26554

3. “Method to control deposition rate instabilities—High power impulse magnetron sputtering deposition of TiO2” A. Kossoy, R.L. Magnusson, T. K. Tryggvason, K. Leosson and S. Ólafsson
J. Vac. Sci. Technol. A 33 (2015) 021514

2. “Challenges in using high power impulse magnetron sputtering for growth of TiO2 films and multilayers: observation of periodic runaway in reactive plasma discharge” S. Shayestehaminzadeh, U. B. Arnalds, R. L. Magnusson, H. Gislason & S. Olafsson
AIP Advances 5 (2015) 117240

1. “Enabling electrochemical reduction of nitrogen to ammonia at ambient conditions through rational catalyst design”, Y. Abghoui, A. L. Garden, S. Björgvinsdóttir, V.F. Hlynsson, H. Ólafsdóttir & E. Skúlason 
Physical Chemistry Chemical Physics 17, (2015) 4909

Conference proceedings

4. “Transition Metal Nitride Catalysts for Electrochemical Reduction of Nitrogen to Ammonia at Ambient Conditions” Y. Abghoui & E. Skúlason
Procedia Computer Science, 51 (2015) 1897

3. “Computational Study of Electrochemical CO2 Reduction at Transition Metal Electrodes” J. Hussain, E. Skúlason & H. Jónsson 
Procedia Computer Science, 51 (2015) 1865

2. “Modeling Electrochemical Reactions at the Solid-liquid Interface Using Density Functional Calculations” E. Skúlason
Procedia Computer Science, 51 (2015) 1887

1. “Morphology of Tantalum Nitride Thin Films Grown on Fused Quartz by Reactive High Power Impulse Magnetron Sputtering (HiPIMS)” D. O. Thorsteinsson, T. K. Tryggvason & J. T. Gudmundsson 
MRS Proceedings, 1803 (2015)

Book chapter

A.L. Garden, Y. Abghoui & E. Skúlason, “Applications of metal nitrides as electrocatalysts”, in “Novel Catalytic Materials”, eds. J. Hargreaves, A. McFarlane, S. Laassiri, Royal Society of Chemistry, (2018)

Patents

6. “Process for electrolytic production of ammonia from nitrogen using metal sulfide catalysts” E. Skúlason & Y. Abghoui, Atmonia ehf., Priority application (Nov 2018), International application (Nov 2019)

5. “Electrochemical reactions with cyclic varied potential” E. Skúlason & H.D. Flosadóttir, Atmonia ehf., Priority application (Oct 2018), International application (Oct 2019)

4. “Carbon nanotube catalysts” E. Skúlason, University of Iceland, Priority application (July 2019)

3. “Electroreduction of carbon dioxide on transition metal oxides catalysts” E. Skúlason, University of Iceland, Priority application (April 2018), International application (April 2019)

2. “Electrolytic production of ammonia using transition metal oxides catalysts” E. Skúlason, University of Iceland, Priority application (July 2017), International application (July 2018)

1. “Electrolytic production of ammonia” E. Skúlason, University of Iceland, Priority application (June 2014), International application (June 2015), National phase (submitted Des 2016), granted in; Iceland, USA, China, Russia and Isreal

Heiti verkefnis: Áburður frá lofti og vatni: Frá reikningum til tilrauna/Fertilizer from air and water: From theory to experiments
Verkefnisstjóri: Egill Skúlason, Raunvísindastofnun HÍ
Tegund styrks: Öndvegisstyrkur
Styrktímabil: 2015-2017
Fjárhæð styrks: 125,658 millj. kr. alls
Tilvísunarnúmer Rannís: 152619