Resolve the pore structure and dynamics of Nafion 117: application of high resolution 7Li solid state nuclear magnetic resonance spectroscopy

Chia, Cheng-Hua; Wu, Zhen; Wu, Cheng-Hsien; Cheng, Ren-Hao; Ding, Shangwu

doi:10.1039/c2jm34057g

Cited by 11 publications

(8 citation statements)

References 39 publications

(75 reference statements)

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“…It appears that these single crystalline Pt nanorods closely resemble the hydrophilic water channel structures proposed to exist in Nafion. 15,17,37 Furthermore, these nanowires seem to be clustered together into bundles, which is similar to the proposed basic structure of hydrated Nafion 15 where the hydrophilic regions of Nafion are collections of rod-like inverted cylindrical micelles. Thus, under these specific conditions, the hydrophilic regions of Nafion's internal structure appear to be acting as a template for the growth of the 1D Pt nanowires.…”

Section: ■ Resultssupporting

confidence: 72%

“…The limited growth rate, due to the significant number of nuclei created, enables these particles to be templated by the hydrated nanostructure in Nafion, creating Pt dendritic structures that are similar to the cylindrical micelle structure proposed for the hydrophilic regions of Nafion. 15,17,37 ■ CONCLUSIONS The deposition of Pt nanostructures into a Nafion membrane was demonstrated and characterized, revealing the influence of the specific reaction conditions, in particular the pH gradient across the membrane. A variety of nanostructures were observed, from isolated nanoparticles, to those created through coalescence of multiple particles, to highly dendritic structures.…”

Section: ■ Discussionmentioning

confidence: 99%

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Synthesis and Characterization of Diverse Pt Nanostructures in Nafion

Ingle

Sode²,

Martens

et al. 2014

Langmuir

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With the aid of TEM characterization, we describe two distinct Pt nanostructures generated via the electroless reduction of Pt(NH3)4(NO2)2 within Nafion. Under one set of conditions, we produce bundles of Pt nanorods that are 2 nm in diameter and 10-20 nm long. These bundled Pt nanorods, uniformly distributed within 5 μm of the Nafion surface, are strikingly similar to the proposed hydrated nanomorphology of Nafion, and therefore strongly suggestive of Nafion templating. By altering the reaction environment (pH, reductant strength, and Nafion hydration), we can also generate nonregular polyhedron Pt nanoparticles that range in size from a few nanometers in diameter up to 20 nm. These Pt nanoparticles form a dense Pt layer within 100-200 nm from the Nafion surface and show a power-law dependence of particle size and distribution on the distance from the Nafion membrane surface. Control over the distribution and the type of Pt nanostructures in the surface region may provide a cost-effective, simple, and scaleable pathway for enhancing manufacturability, activity, stability, and utilization efficiency of Pt catalysts for electrochemical devices.

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Section: ■ Resultssupporting

confidence: 72%

Section: ■ Discussionmentioning

confidence: 99%

Synthesis and Characterization of Diverse Pt Nanostructures in Nafion

Ingle

Sode²,

Martens

et al. 2014

Langmuir

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“…The Li + transference numbers (t Li+ ) was calculated as 0.58 by using the Bruce‐ Vincent‐Evans (BVE) technique (Figure 2 d). [32] The solid‐state 7 Li‐NMR spectra showed that the full width at half maximum (FWHM) of LPC‐2 was narrower than that of LiI@P 1,1 I‐2 % (Figure 3 b), suggesting that the ordered nanochannel of COFs effectively promoted the migration of lithium ions [33, 34] …”

Section: Methodsmentioning

confidence: 99%

Liquid‐Like Phase of N,N‐Dimethylpyrrolidinium Iodide Impregnated into COFs Endows Fast Lithium Ion Conduction in the Solid State

et al. 2021

Chemistry A European J

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“…Nafion layers are known to possess a complex structure with structural heterogeneity on multiple spatial scales from 0.1 to 100 nm with a wide range of pore sizes and channel structure. [37,38] As a result it is experimentally very difficult to define the exact location of hemoglobin within such layers as it may occupy some of the larger pores. Nevertheless resulting from the 3 step dropcasting procedure a large amount will remain embedded between the two Nafion matrices, within the 'sandwich'.…”

Section: Optical Microscopymentioning

confidence: 99%