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Pioneering non-precious metal catalysts for sustainable water electrolysis: from development to utilization
Umeå University, Faculty of Science and Technology, Department of Physics.ORCID iD: 0009-0000-6601-8375
2025 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Imagine a future where our cars, factories, and homes run without polluting the air. That is the idea behinda fossil-free future, a world where we no longer rely on coal, oil, or gas, but instead use clean, renewableenergy sources. One of the most promising options to make this future possible is hydrogen. Althoughhydrogen is the most abundant element in the universe, it is not available as a free resource on Earth;instead, it can be produced from water via electrolysis powered by electricity. What makes it special is itsrole as an energy carrier: it stores and delivers clean energy, and when used, it produces only water, notcarbon dioxide. This makes hydrogen the perfect companion for solar and wind power, helping us keep thelights on, power vehicles, and even run industries, all without burning fossil fuels.

Electrolyzer technology offers a direct and sustainable method for producing hydrogen from water.However, current systems depend heavily on precious metals such as Pt, Ir, and Ru, posing a significantbarrier to scalability. Addressing this challenge requires major advances in materials science to minimize theuse of scarce metals and promote the widespread use of electrolyzers. In our work, we demonstrate thatnon-precious, earth-abundant electrocatalysts can consistently deliver high efficiency and long-termstability. We developed novel synthesis routes to produce highly defective and porous nanomaterials frommetal alloys and mixed oxides to transition metal dichalcogenides. We studied their intrinsic catalyticactivity and learned to tune their performance under both alkaline and acidic conditions. This allowed us tofurther study these cost-effective electrocatalysts in anion (and proton) exchange membrane electrolyzers.Our studies show that these materials can achieve competitive efficiency and durability, providing a viablepathway to reduce reliance on noble metals and accelerate the commercialization of large-scale waterelectrolysis.

Abstract [sv]

Föreställ dig en framtid där våra bilar, fabriker och hem drivs utan att förorena luften. Det är idén bakom en fossilfri framtid, en värld där vi inte längre är beroende av kol, olja eller gas, utan istället använder rena och förnybara energikällor. Ett av de mest lovande alternativen för att göra denna framtid möjlig är vätgas. Även om väte är det mest förekommande grundämnet i universum, finns det inte som en fri tillgänglig resurs på jorden; vätgas kan istället framställas ur vatten genom elektrolys som drivs av elektricitet. Det som gör vätgas särskilt intressant är dess egenskap att vara en energibärare, vätgas kan lagra och leverera ren energi, och när den används bildas endast vatten, inte koldioxid. Detta gör vätgas till det perfekta komplementet till sol och vindkraft, eftersom den kan bidra till att hålla lamporna tända, driva fordon och till och med försörja industrier, allt utan att bränna fossila bränslen.

Elektrolysteknik erbjuder en direkt och hållbar metod för att producera vätgas ur vatten. Dagens system är dock starkt beroende av ädelmetaller som platina (Pt), iridium (Ir) och rutenium (Ru), vilket innebär ett betydande hinder för storskalig tillämpning. För att övervinna denna utmaning krävs stora framsteg inom materialvetenskap, med fokus på att minimera användningen av sällsynta metaller och snabba på utveckling och installation av elektrolysteknik. I vårt arbete visar vi att icke-ädla, vanligt förekommande elektrokatalysatorer kan uppnå både hög effektivitet och långsiktig stabilitet. Vi har utvecklat nya syntesmetoder för att framställa defektrika och porösa nanomaterial från metalllegeringar och metalloxidlegeringar till blandningar av övergångsmetaller och dikalcogenider. Vi har undersökt deras katalytiska aktivitet och lärt oss att optimera deras prestanda under både alkaliska och sura reaktionsförhållanden. Detta har gjort det möjligt för oss att i nästa steg studera dessa kostnadseffektiva elektrokatalysatorer i elektrolysörer med anjon och protonutbytande membran. Våra studier visar att dessa material kan uppnå konkurrenskraftig effektivitet och hållbarhet, och därigenom påvisa en möjlig utveckling för att minska beroendet av ädelmetaller och påskynda kommersialiseringen av storskalig vattensönderdelning.

Place, publisher, year, edition, pages
Umeå University, 2025. , p. 78
Keywords [en]
Water electrolysis, electrocatalysts, hydrogen evolution reaction, oxygen evolution reaction.
National Category
Materials Chemistry Energy Systems
Identifiers
URN: urn:nbn:se:umu:diva-245905ISBN: 978-91-8070-799-2 (print)ISBN: 978-91-8070-800-5 (electronic)OAI: oai:DiVA.org:umu-245905DiVA, id: diva2:2009203
Public defence
2025-11-21, KBE301 - Lilla hörsalen, KBC huset, Umeå, 09:00 (English)
Opponent
Supervisors
Available from: 2025-10-31 Created: 2025-10-27 Last updated: 2025-10-28Bibliographically approved
List of papers
1. Non-stoichiometric NiFeMo solid solutions; tuning the hydrogen adsorption energy via molybdenum incorporation
Open this publication in new window or tab >>Non-stoichiometric NiFeMo solid solutions; tuning the hydrogen adsorption energy via molybdenum incorporation
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2022 (English)In: Advanced Materials Interfaces, ISSN 2196-7350, Vol. 9, no 34, article id 2201214Article in journal (Refereed) Published
Abstract [en]

Solution precursor plasma spraying is used to produce catalytic trimetallic coatings containing Ni, Fe and Mo directly onto stainless-steel mesh, Ni foam and carbon paper. The resulting material is mostly comprised of face centered cubic FeNi3 alloy forming a highly porous coating with nanostructured features. The addition of Mo (up to ≈14 at%) generates no new crystal phases but only an increase in the lattice parameter, indicating the formation of FeNi3Mox solid solutions. The FeNi3Mox solid solutions are used as electrocatalyst for the hydrogen evolution reaction (HER) in alkaline media. The addition of Mo increases the HER activity significantly reaching an optimum performance at ≈9 at% Mo (FeNi3Mo0.40) with an overpotential at −10 mA cm−2 of 112 mV and a Tafel slope of 109 mV dec−1. The enhanced HER activity is attributed to the formation of a FeNi3Mox solid solution with an increased work function that is correlated to smaller hydrogen adsorption energies. Theoretical activity maps reveal that sites near superficial Mo atoms forms catalytic hot spots and are responsible for the observed activity.

Place, publisher, year, edition, pages
John Wiley & Sons, 2022
Keywords
catalytic activity maps, electrocatalysis, hydrogen evolution, NiFeMo, solid solution, ternary alloy, work function
National Category
Condensed Matter Physics Physical Chemistry
Identifiers
urn:nbn:se:umu:diva-200394 (URN)10.1002/admi.202201214 (DOI)000864415500001 ()2-s2.0-85139435922 (Scopus ID)
Available from: 2022-10-25 Created: 2022-10-25 Last updated: 2025-10-27Bibliographically approved
2. Distorted octahedral sites drive early formation and stabilisation of nickel oxyhydroxides in trimetallic nickel–iron–molybdenum oxides
Open this publication in new window or tab >>Distorted octahedral sites drive early formation and stabilisation of nickel oxyhydroxides in trimetallic nickel–iron–molybdenum oxides
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2025 (English)In: Communications Materials, E-ISSN 2662-4443, Vol. 6, no 1, article id 115Article in journal (Refereed) Published
Abstract [en]

Trimetallic nickel–iron–molybdenum oxides are excellent electrocatalysts for alkaline water electrolysis despite experiencing severe molybdenum dissolution. While the impact of molybdenum on fresh samples is well-understood, its substantial loss during operation without compromising performance presents a unique puzzle. Here, we show that the initial presence of molybdenum induces the formation of nickel vacancies and distorts octahedral nickel sites. This structural distortion induces charge transfer between lattice oxygen and nickel, inducing an early formation and stabilization of active nickel oxyhydroxides. Even after complete molybdenum leaching and transitioning into a bimetallic nickel-iron oxide, the catalyst retains its exceptional performance due to the persistence of distorted octahedral nickel sites. Understanding this process enables the exploration of alternative metals that could induce similar structural distortions, as well as inspire similar strategies in other electrocatalysts. (Figure presented.)

Place, publisher, year, edition, pages
Springer Nature, 2025
National Category
Materials Chemistry
Identifiers
urn:nbn:se:umu:diva-240309 (URN)10.1038/s43246-025-00842-y (DOI)001502814300001 ()2-s2.0-105007544299 (Scopus ID)
Funder
The Kempe Foundations, JCK-2132Carl Tryggers foundation , CTS 21-1581Olle Engkvists stiftelse, 219-0116Swedish Research Council, 2021-04629Swedish Foundation for Strategic Research, ID22-0062
Available from: 2025-06-24 Created: 2025-06-24 Last updated: 2025-10-27Bibliographically approved
3. Hydrogen evolution mediated by sulfur vacancies and substitutional Mn in few-layered molybdenum disulfide
Open this publication in new window or tab >>Hydrogen evolution mediated by sulfur vacancies and substitutional Mn in few-layered molybdenum disulfide
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2024 (English)In: Materials Today Energy, ISSN 2468-6069, Vol. 41, article id 101524Article in journal (Refereed) Published
Abstract [en]

MoS2 is widely praised as a promising replacement for Pt as an electrocatalyst for the hydrogen evolution reaction (HER), but even today, it still suffers from low performance. This issue is tackled by using Mn3+ as a surface modifier to trigger sulfur vacancy formation and enhance electron transport in few-layered 2H MoS2. Only 10% of Mn is sufficient to transform the semiconductive MoS2 into an active HER electrocatalyst. The insertion of Mn reduces both HER onset potential and Tafel slope which allows reaching 100 mA/cm2 at an overpotential of 206 mV, ten times larger of what undoped MoS2 can achieve. The enhanced activity arises because Mn3+ introduces electronic states near the conduction band, promotes sulfur vacancies, and increases the hydrogen adsorption. In addition to its facile production and extended shelf-life, Mn–MoS2 exhibits an efficiency of 73% at 800 mA/cm2 and 2.0 V when used in proton exchange membrane water electrolyzers.

Place, publisher, year, edition, pages
Elsevier, 2024
Keywords
Hydrogen evolution reaction, Manganese, Proton exchange membrane, Sulfur vacancy, Water electrolysis
National Category
Materials Chemistry Other Physics Topics
Identifiers
urn:nbn:se:umu:diva-221781 (URN)10.1016/j.mtener.2024.101524 (DOI)001198873200001 ()2-s2.0-85185894201 (Scopus ID)
Funder
Swedish Research Council, 2018-03937The Kempe Foundations, JCK-2132The Kempe Foundations, JCK-2021Carl Tryggers foundation , CTS 21-1581Swedish Foundation for Strategic ResearchSwedish National Infrastructure for Computing (SNIC)
Available from: 2024-03-19 Created: 2024-03-19 Last updated: 2025-10-27Bibliographically approved
4. Fabrication of nickel-molybdenum-based catalyst coated substrates using precursor solution plasma spraying: a transferable technique for high-performance anion exchange membrane water electrolysers
Open this publication in new window or tab >>Fabrication of nickel-molybdenum-based catalyst coated substrates using precursor solution plasma spraying: a transferable technique for high-performance anion exchange membrane water electrolysers
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(English)Manuscript (preprint) (Other academic)
National Category
Materials Chemistry Energy Systems
Identifiers
urn:nbn:se:umu:diva-245841 (URN)
Available from: 2025-10-27 Created: 2025-10-27 Last updated: 2025-10-27Bibliographically approved
5. Plasma sprayed Ni-Fe-Mo oxide as high-performance anode for anion exchange membrane water electrolysis with over 1200 hours of operation
Open this publication in new window or tab >>Plasma sprayed Ni-Fe-Mo oxide as high-performance anode for anion exchange membrane water electrolysis with over 1200 hours of operation
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(English)Manuscript (preprint) (Other academic)
National Category
Materials Chemistry Energy Systems
Identifiers
urn:nbn:se:umu:diva-245842 (URN)
Available from: 2025-10-27 Created: 2025-10-27 Last updated: 2025-10-27Bibliographically approved

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