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Title: Investigation of the Interaction between Nafion Ionomer and Surface Functionalized Carbon Black Using Both Ultrasmall Angle X-ray Scattering and Cryo-TEM

Abstract

In making a catalyst ink, the interaction between Nafion ionomer and catalyst support are the key factors that directly affect both ionic conductivity and electronic conductivity of the catalyst layer in a membrane electrode assembly (MEA). One of the major aims of this investigation is to understand the behavior of the catalyst support, Vulcan XC-72 (XC-72) aggregates, in the existence of the Nafion ionomer in a catalyst ink to fill the knowledge gap of the interaction of these components. The dispersion of catalyst ink not only depends on the solvent, but also depends on the interaction of Nafion and carbon particles in the ink. The interaction of Nafion ionomer particles and XC-72 catalyst aggregates in liquid media was studied using ultra small angle x-ray scattering (USAXS) and cryogenic TEM techniques. Carbon black XC-72) and functionalized carbon black systems were introduced to study the interaction behaviors. A multiple curve fitting was used to extract the particle size and size distribution from scattering data. The results suggest that the particle size and size distribution of each system changed significantly in Nafion + XC-72 system, Nafion + NH2-XC72 system, and Nafion + SO3H-XC-72 system, which indicates that an interaction among these components (i.e.more » ionomer particles and XC-72 aggregates) exists. The cryogenic TEM, which allows for the observation the size of particles in a liquid, was used to validate the scattering results and shows excellent agreement.« less

Authors:
; ; ; ; ; ; ; ORCiD logo
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science - Office of Basic Energy Sciences - Scientific User Facilities Division
OSTI Identifier:
1373599
DOE Contract Number:
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: ACS Applied Materials and Interfaces; Journal Volume: 9; Journal Issue: 7
Country of Publication:
United States
Language:
English
Subject:
Catalyst Ink; Cryo-TEM; Dispersion; Fuel Cell; Nafion Ionomer; Pt/C Catalyst; USAXS; X-ray Scattering

Citation Formats

Yang, Fan, Xin, Le, Uzunoglu, Aytekin, Qiu, Yang, Stanciu, Lia, Ilavsky, Jan, Li, Wenzhen, and Xie, Jian. Investigation of the Interaction between Nafion Ionomer and Surface Functionalized Carbon Black Using Both Ultrasmall Angle X-ray Scattering and Cryo-TEM. United States: N. p., 2017. Web. doi:10.1021/acsami.6b12949.
Yang, Fan, Xin, Le, Uzunoglu, Aytekin, Qiu, Yang, Stanciu, Lia, Ilavsky, Jan, Li, Wenzhen, & Xie, Jian. Investigation of the Interaction between Nafion Ionomer and Surface Functionalized Carbon Black Using Both Ultrasmall Angle X-ray Scattering and Cryo-TEM. United States. doi:10.1021/acsami.6b12949.
Yang, Fan, Xin, Le, Uzunoglu, Aytekin, Qiu, Yang, Stanciu, Lia, Ilavsky, Jan, Li, Wenzhen, and Xie, Jian. Wed . "Investigation of the Interaction between Nafion Ionomer and Surface Functionalized Carbon Black Using Both Ultrasmall Angle X-ray Scattering and Cryo-TEM". United States. doi:10.1021/acsami.6b12949.
@article{osti_1373599,
title = {Investigation of the Interaction between Nafion Ionomer and Surface Functionalized Carbon Black Using Both Ultrasmall Angle X-ray Scattering and Cryo-TEM},
author = {Yang, Fan and Xin, Le and Uzunoglu, Aytekin and Qiu, Yang and Stanciu, Lia and Ilavsky, Jan and Li, Wenzhen and Xie, Jian},
abstractNote = {In making a catalyst ink, the interaction between Nafion ionomer and catalyst support are the key factors that directly affect both ionic conductivity and electronic conductivity of the catalyst layer in a membrane electrode assembly (MEA). One of the major aims of this investigation is to understand the behavior of the catalyst support, Vulcan XC-72 (XC-72) aggregates, in the existence of the Nafion ionomer in a catalyst ink to fill the knowledge gap of the interaction of these components. The dispersion of catalyst ink not only depends on the solvent, but also depends on the interaction of Nafion and carbon particles in the ink. The interaction of Nafion ionomer particles and XC-72 catalyst aggregates in liquid media was studied using ultra small angle x-ray scattering (USAXS) and cryogenic TEM techniques. Carbon black XC-72) and functionalized carbon black systems were introduced to study the interaction behaviors. A multiple curve fitting was used to extract the particle size and size distribution from scattering data. The results suggest that the particle size and size distribution of each system changed significantly in Nafion + XC-72 system, Nafion + NH2-XC72 system, and Nafion + SO3H-XC-72 system, which indicates that an interaction among these components (i.e. ionomer particles and XC-72 aggregates) exists. The cryogenic TEM, which allows for the observation the size of particles in a liquid, was used to validate the scattering results and shows excellent agreement.},
doi = {10.1021/acsami.6b12949},
journal = {ACS Applied Materials and Interfaces},
number = 7,
volume = 9,
place = {United States},
year = {Wed Feb 08 00:00:00 EST 2017},
month = {Wed Feb 08 00:00:00 EST 2017}
}
  • Ionomer morphology has received extensive studies due to its interesting characteristics in the molecular aggregation of ionic groups. The strong scattering peak in the small-angle X-ray scattering (SAXS) profile has been accounted for by several models. From the multiphase relaxation point of view, Eisenberg et al. proposed that the ionic multiplets were the basic unit of aggregation. The ionic aggregates were surrounded by a spherical region of polymer backbones of restricted mobility. Some overlap of the restricted regions of the ionic phases could be characterized by a high-temperature relaxation relative to the one for the surrounding matrix. The electron densitymore » inhomogeneity in a length scale comparable to the average distance between two adjacent multiplets leads to an ionic peak in the SAXS profile. The SAXS profiles of ionomers at different temperatures depended on the counterions and the method of sample preparation. In this paper the authors report SAXS measurements of an ionomer which has undergone different thermal treatment. Extra care was taken in correcting the thermal expansion which was responsible for the primary change in the SAXS profile at different temperatures. The authors used an approach developed by Fischer and Gehrke et al. The modified Porod law and the inverse Fourier transform were used to evaluate the microstructure parameters.« less
  • No abstract prepared.
  • Nanoparticle electrodeposition is a simple and scalable approach to synthesizing supported nanoparticles. Used with a deep eutectic solvent (DES), surface nanoparticles can be assembled and exhibit unique surface charge separation when the DES is adsorbed on the nanoparticle surface. Key to understanding and controlling the assembly and the capacitance is a thorough understanding of surface particle mobility and charge screening, which requires an in-situ approach. In this study, Pb particle formation, size, shape and capacitance are resolved in a 1:2 choline Cl : urea deep eutectic solvent whilst sweeping the cell potential in the range: 0.2 V to –1.2 Vmore » (vs. Ag/AgCl). These system parameters were resolved using a complementary suite of sample-rotated small angle X-ray scattering (SR-SAXS) and electrochemical impedance spectroscopy (EIS), which are presented and discussed in detail. This approach is able to show that both particle and ion transport are impeded in the DES, as aggregation occurs over the course of 6 minutes, and dissolved Pb ions accumulate and remain near the surface after a nucleation pulse is applied. The DES-Pb interactions strongly depend on the cell potential as evidenced by the specific differential capacitance of the Pb deposit, which has a maximum value of 2.5 +/– 0.5 F g –1 at –1.0 V vs. Ag/AgCl. Together, the SR-SAXS-EIS approach is able to characterize the unique nanoparticle capacitance, mobility and ion mobility in a DES and can be used to study a wide range of nanoparticle deposition systems in-situ.« less
  • We present the upgrade and present status of the ultrasmall-angle x-ray scattering (USAXS) beamline BW4 at the Hamburg Synchrotronstrahlungslabor. In order to extend the accessible scattering vector range, new small-angle setups have been established, making use of the high flux and small divergence of BW4. In standard transmission geometry using a beam size of B=400x400 {mu}m{sup 2} (horizontalxvertical), typical small-angle resolution ranges from d{sub max}=90 to 650 nm, depending on sample-to-detector distance. Additionally a new microfocus option has been established. This microfocus option allows reducing the sample size by one order of magnitude. Using parabolic beryllium compound refractive lenses, amore » new standard beam size of B=65x35 {mu}m{sup 2} (horizontalxvertical) can be provided. The {mu}-SAXS resolution is as high as d{sub max}=150 nm. Using {mu}-SAXS in combination with grazing incidence ({mu}-GISAXS) on a standard noble metal gradient multilayer, we prove the feasibility of {mu}-GISAXS experiments at a second generation source.« less