Pt/Nanoporous Carbon Scaffold Catalyst Layer for Use in Symmetrical Proton Exchange Membrane Fuel Cells
Notice bibliographique
Résumé
Carbon microstructures are an essential component of both the cathode and anode catalyst layer in PEMFCs, typically serving as the catalyst support [1], and it is known that the carbon porosity, surface area, and its hydrophobicity/hydrophilicity have a significant effect on electrocatalytic activity and transport issues. This is due to the impact of the carbon on catalyst dispersion, Nafion distribution, electronic conduction, and mass transport limitations [2-4]. Typically, carbon black is used as the catalyst support because of its high surface area, low cost, good electrical conductivity [4,5], but it is susceptible to corrosion and does not pack uniformly, thus resulting in uncontrolled pathways for reactants/products through the catalyst layer [6,7]. Recently, there has been an increasing interest in using mesoporous carbons as catalyst supports for fuel cell application, due to the better accessibility of the internal carbon surfaces, and the tethered Pt nanoparticles, to the reactants, and better mass transport of reactants and products during fuel cell operation [8,9]. Our team has recently developed a novel nanoporous carbon scaffold (NCS), which is self-supported, scalable, and highly tunable (its monodisperse pore size can be controllably varied from 10 to 100 nm), giving specific surface areas of 200 to 600 m2 g-1. These films are fully percolating, have very low tortuosity and a 90% porosity, good electronic conductivity of 2-10 S cm-1 and are robust [10]. While prior work has involved the preparation and testing of an MEA that contained Pt/NCS on the cathode side of the separator, in this work, the focus was on the first-time testing of a symmetrical cell with Pt/NCS on both sides of a Nafion membrane. Here, the Pt nanoparticles (NPs) were deposited throughout the NCS material by wet impregnation of the chloroplatinic acid precursor (Fig. 1) and then infiltrated with Nafion by drop-casting. The thickness of the Pt/NCS films used in the current study was 25 ± 2 μm, the NCS pore size was 85 nm, and the Pt loading at the cathode was < 1 mg Pt cm-2. The Nafion®117 membrane was sandwiched between two NCS catalyst layers by hot pressing and the performance of these new symmetrical MEAs was evaluated in a fuel cell test station using different temperatures. This presentation will focus on the performance of the symmetrical MEA design in comparison to conventional ink-deposited systems, as well as the durability of these novel materials. Because the NCS has such a uniform structure, discussion will also be focused on the changes observed to the carbon itself as well as to the Pt NP size and distribution after testing under PEMFC conditions. References [1] E.H. Majlan, D. Rohendi, W.R.W. Daud, T. Husaini, M.A. Haque, Renewable and Sustainable Energy Reviews, 89,2018, 117-134. [2] C. Arbizzani, S. Righi, F. Soavi, M. Mastragostino, International Journal of Hydrogen Energy, 36, 2011,5038-5046. [3] J.A. Prithi, N. Rajalakshmi, G. Ranga Rao, International Journal of Hydrogen Energy,43, 2018, 4716-4725. [4] A. Bharti, G. Cheruvally, Journal of Power Sources, 360, 2017,196-205. [5] D.V. Dao, G. Adilbish, I. Lee, Y. Yu, International Journal of Hydrogen Energy, 44, 2019, 24580-24590. [6] M.F.L. De Volder, S.H. Tawfick, R.H. Baughman, A.J. Hart science, 339, 2013, 535-539. [7] C.A. Reiser, L. Bregoli, T.W. Patterson, J.S. Yi, J.D. Yang, M.L. Perry, T.D. Jarvi, Electrochem. Solid State Lett., 8, 2005, A273. [8] E. Antolini, Applied Catalysis B: Environmental, 88, 2009, 1-24. [9]S. Songa, Y. Liang, Z. Li, Y. Wang, R. Fu, D. Wu, P. Tsiakarasc, Applied Catalysis B: Environmental, 98, 2010, 132-137. [10] V. Birss, X. Li, D. Banham, D. Y. Kwok, Porous carbon films. PCT/CA2015/000516, 2015. Figure 1. FESEM image of Pt (open circles) within the NCS film. Figure 1
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».