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Microwave-Induced Structural Ordering of Resilient Nanostructured L10-FePt Catalysts for Oxygen Reduction Reaction
Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.ORCID-id: 0000-0002-6830-2174
Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.ORCID-id: 0000-0001-9239-0541
Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.ORCID-id: 0000-0002-5210-2645
Linköping University. (Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM))ORCID-id: 0000-0001-9140-6724
Visa övriga samt affilieringar
(Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
Abstract [en]

We show how structurally ordered L10 face-centered tetragonal (fct) FePt nanoparticles are produced by a solid-state microwave-assisted synthesis method. The structural phase as well as the incorporated Fe into the nanoparticles is confirmed by X-ray diffraction and high resolution high-angle annular dark field scanning transmission electron microscopy experiments. The prepared particles exhibit a remarkable resilience toward crystallite growth at high temperatures. Directly correlated to the L10 phase, the best oxygen reduction reaction (ORR) characteristics are achieved for particles with a 1:1 Fe:Pt atomic ratio and an average size of ~2.9 nm where Pt-specific evaluation provided a high mass and specific activity of ~570 A/gPt and ~600 μA/cm2Pt respectively. Our results demonstrate that well-structured catalysts possessing activities vastly exceeding Pt/C (~210 A/gPt & ~250 μA/cm2Pt), can be synthesized through a fast and highly eco-friendly method. We note that the achieved mass activity represent a significant leap toward the theoretical maximum for fully ordered FePt nanoparticles.

Nyckelord [en]
Proton exchange membrane fuel cell, platinum iron, Oxygen reduction reaction, microwave synthesis
Nationell ämneskategori
Nanoteknik Annan materialteknik
Forskningsämne
materialvetenskap; nanomaterial; nanopartiklar; fasta tillståndets fysik
Identifikatorer
URN: urn:nbn:se:umu:diva-158495OAI: oai:DiVA.org:umu-158495DiVA, id: diva2:1307776
Forskningsfinansiär
Vetenskapsrådet, 2017-04862Energimyndigheten, 45419-1Interreg NordÅForsk (Ångpanneföreningens Forskningsstiftelse), 15-483Vetenskapsrådet, 2016‐04412Stiftelsen för strategisk forskning (SSF), RIF 14‐0074Vetenskapsrådet, 2018-03937Stiftelsen Olle Engkvist Byggmästare, 186-0637Tillgänglig från: 2019-04-29 Skapad: 2019-04-29 Senast uppdaterad: 2019-04-29
Ingår i avhandling
1. Innovations in nanomaterials for proton exchange membrane fuel cells
Öppna denna publikation i ny flik eller fönster >>Innovations in nanomaterials for proton exchange membrane fuel cells
2019 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Alternativ titel[sv]
Utveckling av nanomaterial för polymerelektrolytbränsleceller
Abstract [en]

Hydrogen technologies are rapidly receiving increased attention as it offers a renewable energy alternative to the current petroleum-based fuel infrastructure, considering that continued large-scale use of such fossil fuels will lead to disastrous impacts on our environment. The proton exchange membrane fuel cell should play a significant role in a hydrogen economy since it enables convenient and direct conversion of hydrogen into electricity, thus allowing the use of hydrogen in applications particularly suited for the transportation industry. To fully realize this, multiple engineering challenges as well as development of advanced nanomaterials must however be addressed.

In this thesis, we present discoveries of new innovative nanomaterials for proton exchange membrane fuel cells by targeting the entire membrane electrode assembly. Conceptually, we first propose new fabrication techniques of gas diffusion electrodes based on helical carbon nanofibers, where an enhanced three-phase boundary was noted in particular for hierarchical structures. The cathode catalyst, responsible for facilitating the sluggish oxygen reduction reaction, was further improved by the synthesis of platinum-based nanoparticles with an incorporated secondary metal (iron, yttrium and cobalt). Here, both solvothermal and high-temperature microwave syntheses were employed. Catalytic activities were improved compared to pure platinum and could be attributed to favorably shifted oxygen adsorption energies as a result of successful incorporation of the non-precious metal. As best exemplified by platinum-iron nanoparticles, the oxygen reduction reaction was highly sensitive to both metal composition and the type of crystal structure. Finally, a proton exchange membrane based on fluorine and sulfonic acid functionalized graphene oxide was prepared and tested in hydrogen fuel cell conditions, showing improvements such as lowered hydrogen permeation and better structural stability. Consequently, we have demonstrated that there is room for improvement of multiple components, suggesting that more powerful fuel cells can likely be anticipated in the future.

Ort, förlag, år, upplaga, sidor
Umeå: Umeå University, 2019. s. 88
Nyckelord
Fuel Cells, Membrane Electrode Assembly, Oxygen Reduction Reaction, Platinum alloy catalyst, Nanoparticles, Gas Diffusion Electrode, Proton Exchange Membrane
Nationell ämneskategori
Energisystem Nanoteknik Annan materialteknik Annan kemiteknik Den kondenserade materiens fysik
Forskningsämne
materialvetenskap; fasta tillståndets fysik
Identifikatorer
urn:nbn:se:umu:diva-158501 (URN)978-91-7855-044-9 (ISBN)
Disputation
2019-05-28, N460, Naturvetarhuset, Umeå, 10:15 (Engelska)
Opponent
Handledare
Tillgänglig från: 2019-05-07 Skapad: 2019-04-29 Senast uppdaterad: 2019-05-06Bibliografiskt granskad

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Sandström, RobinGracia-Espino, EduardoAnnamalai, AlagappanEkspong, JoakimBarzegar, Hamid RezaWågberg, Thomas

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Sandström, RobinGracia-Espino, EduardoAnnamalai, AlagappanPersson, PerPersson, IngemarEkspong, JoakimBarzegar, Hamid RezaWågberg, Thomas
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Institutionen för fysik
NanoteknikAnnan materialteknik

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