title: Investigation of a catalyst ink dispersion using both ultra-small-angle X-ray scattering and cryogenic TEM.
abstract: The dispersion of Nafion ionomer particles and Pt/C catalyst aggregates in liquid media was studied using both ultra-small-angle X-ray scattering (USAXS) and cryogenic TEM. A systematic approach was taken to study first the dispersion of each component (i.e., ionomer particles and Pt/C aggregates), then the combination of the components, and last the catalyst ink. Multiple-level curve fitting was used to extract the particle size, size distribution, and geometry of the Pt/C aggregates and the Nafion particles in liquid media from the scattering data. The results suggest that the particle size, size distribution, and geometry are not uniform throughout the systems but rather vary significantly. It was found that the interaction of each component (i.e., the Nafion ionomer particles and the Pt/C aggregates) occurs in the dispersion. Cryogenic TEM was used to observe the size and geometry of the particles in liquid directly and to validate the scattering results. The TEM results showed excellent agreement.
authors.affiliation: Department of Mechanical Engineering, Indiana University—Purdue University Indianapolis, Indianapolis, Indiana 46202, United States.
authors.forename: Fan
authors.initials: F
authors.lastname: Xu
authors.forename: HangYu
authors.initials: H
authors.lastname: Zhang
authors.forename: Jan
authors.initials: J
authors.lastname: Ilavsky
authors.forename: Lia
authors.initials: L
authors.lastname: Stanciu
authors.forename: Derek
authors.initials: D
authors.lastname: Ho
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Justice
authors.forename: Horia I
authors.initials: HI
authors.lastname: Petrache
authors.forename: Jian
authors.initials: J
authors.lastname: Xie
mesh_terms: D002244:Carbon / Q000737:chemistry; D002384:Catalysis; D005465:Fluorocarbon Polymers / Q000737:chemistry; D005990:Glycerol / Q000737:chemistry; D007281:Ink; D046529:Microscopy, Electron, Transmission; D010316:Particle Size; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D053838:Scattering, Small Angle; D012997:Solvents / Q000737:chemistry; D053260:Soot / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D005465:Fluorocarbon Polymers; D000644:Quaternary Ammonium Compounds; D012997:Solvents; D053260:Soot; C040402:perfluorosulfonic acid; D002244:Carbon; C009405:tetrabutylammonium; D005990:Glycerol