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Nafion
About: Nafion is a research topic. Over the lifetime, 9110 publications have been published within this topic receiving 320865 citations.
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TL;DR: In this paper, sulfonated graphene oxide-silica (S-GO-SiO2) nanohybrid particles were obtained first and the FTIR, TGA, XRD, Raman, AFM, FE-SEM and EDX characterizations were employed to confirm the successful decoration of SiO2 onto GO surface and the attachment of sulfonic acid groups onto the GO−SiO 2 surface.
Abstract: In the current study, sulfonated graphene oxide–silica (S-GO–SiO2) nanohybrid particles were obtained first. The FTIR, TGA, XRD, Raman, AFM, FE-SEM and EDX characterizations were employed to confirm the successful decoration of SiO2 onto GO surface and the attachment of sulfonic acid groups onto the GO–SiO2 surface. Then, S-GO–SiO2/Nafion proton exchange membranes (PEMs) were prepared via solution casting. S-GO–SiO2 had a good dispersibility inside the membrane matrix. The increased water uptake and the incorporated –SO3H groups bestowed a large increase in proton conductivity upon these composite PEMs. Meanwhile, the barrier effect of two-dimensional S-GO–SiO2 contributed to the obvious reduction in methanol permeability of the composite PEMs, as a result of the increased tortuosity of the transport channels. Therefore, novel S-GO–SiO2/Nafion PEMs with enhanced selectivity (the ratio of proton conductivity to methanol permeability) were obtained. Even under harsh conditions, such as high methanol concentration and/or increased temperature, the membrane selectivity of S-GO–SiO2/Nafion composite membranes was still nearly two-orders-of-magnitude higher than that of the recast Nafion membrane. It renders this type of composite PEMs a very promising candidate for the application in DMFC. All the conclusions were demonstrated by various characterizations, such as (FE-) SEM, TEM, AFM, FTIR, TGA, water uptake, etc.
113 citations
TL;DR: In this article, a composite membrane fabricated by sandwiching a monolayer graphene between two thin Nafion membranes is proposed to take advantage of the selective permeability to only protons.
113 citations
TL;DR: In this article, the status of research and development of polymer electrolyte membranes (PEMs) for direct methanol fuel cells (DMFCs) is described and a review of membrane properties is carried out on the basis of thermal stability, methanoline crossover and proton conductivity.
113 citations
TL;DR: In this article, a double-layer membrane modified electrode was used for the determination of epinephrine (EP) under normal physiological pH conditions, the logarithm of the catalytic current of EP vs. its concentration showed a linear relation.
113 citations
TL;DR: Nafion, whose side-chain length is intermediate of the three polymers studied, is found to have the most mobile polymer side-chains at the higher level of hydration, suggesting that there could be an optimal side- chain length in these systems.
Abstract: The Nafion, Dow and Aciplex systems – where the prime differences lies in the side-chain length – have been studied by molecular dynamics (MD) simulation under standard pressure and temperature conditions for two different levels of hydration: 5 and 15 water molecules per (H)SO3 end-group. Structural features such as water clustering, water-channel dimensions and topology, and the dynamics of the hydronium ions and water molecules have all been analysed in relation to the dynamical properties of the polymer backbone and side-chains. It is generally found that mobility is promoted by a high water content, with the side-chains participating actively in the H3O+/H2O transport mechanism. Nafion, whose side-chain length is intermediate of the three polymers studied, is found to have the most mobile polymer side-chains at the higher level of hydration, suggesting that there could be an optimal side-chain length in these systems. There are also some indications that the water-channel network connectivity is optimal for high water-content Nafion system, and that this could explain why Nafion appears to exhibit the most favourable overall hydronium/water mobility.
112 citations