Topic
Nafion
About: Nafion is a research topic. Over the lifetime, 9110 publications have been published within this topic receiving 320865 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this paper, a high temperature direct methanol fuel cells (DMFCs) were used as fillers in composite Nafion membranes for application in high temperature DMFCs, and the powder physico-chemical properties were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), Xray photoelectron spectroscopy (XPS), and pH measurements.
215 citations
TL;DR: In this article, a simple scanning electron microscopy-energy dispersive spectroscopy analysis was used to estimate that ∼ 13% of the platinum initially in the cathode was transported into the membrane following 3000 potential cycles.
Abstract: Dissolution at the cathode and subsequent transport of platinum to the other cell components causes catalyst degradation in proton exchange membrane (PEM) fuel cells. Deposition of platinum in Nafion membrane was observed after potential cycling under hydrogen/air conditions. The deposited Pt formed a band in the ionomer, and a straightforward model was proposed to describe its location. The predicted position of the Pt band agreed with the experimental data. A simple scanning electron microscopy-energy dispersive spectroscopy analysis was used to estimate that ∼ 13% of the platinum initially in the cathode was transported into the membrane following 3000 potential cycles.
215 citations
TL;DR: The properties of confined water and diffusive proton-transfer kinetics in the nanoscopic water channels of Nafion fuel cell membranes at various hydration levels are compared to water in a series of well-characterized AOT reverse micelles with known water nanopool sizes using the photoacid pyranine as a molecular probe.
Abstract: The properties of confined water and diffusive proton-transfer kinetics in the nanoscopic water channels of Nafion fuel cell membranes at various hydration levels are compared to water in a series of well-characterized AOT reverse micelles with known water nanopool sizes using the photoacid pyranine as a molecular probe. The side chains of Nafion are terminated by sulfonate groups with sodium counterions that are arrayed along the water channels. AOT has sulfonate head groups with sodium counterions that form the interface with the reverse micelle's water nanopool. The extent of excited-state deprotonation is observed by steady-state fluorescence measurements. Proton-transfer kinetics and orientational relaxation are measured by time-dependent fluorescence using time-correlated single photon counting. The time dependence of deprotonation is related to diffusive proton transport away from the photoacid. The fluorescence reflecting the long time scale proton transport has an approximately t-0.8 power law decay in contrast to bulk water, which has a t-3/2 power law. For a given hydration level of Nafion, the excited-state proton transfer and the orientational relaxation are similar to those observed for a related size AOT water nanopool. The effective size of the Nafion water channels at various hydration levels are estimated by the known size of the AOT reverse micelles that display the corresponding proton-transfer kinetics and orientational relaxation.
214 citations
TL;DR: In this paper, an easy and effective method for producing low methanol-crossover membranes is developed by dispersing sulfonated graphene oxide (SGO) into a Nafion matrix.
213 citations
TL;DR: In this article, the potentialities of PEEK-based polymers are discussed, pointing out the main benefits and drawbacks of these proton exchange membranes for fuel cell applications, and the use of sulfonated PEEK with cardo-group (PEEK-WC) is particularly stressed.
212 citations