Electrocatalysts in Polymer Electrolyte Membrane Fuel Cells

Lyth, Stephen M.; Mufundirwa, Albert

doi:10.1002/9783527813599.ch32

Cited by 4 publications

(2 citation statements)

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“…Small-angle X-ray scattering (SAXS) is a useful method for characterizing the structure of catalyst particles for fuel cells and other applications [1][2]. In these applications, the nanometer-sized catalyst particles, typically made of platinum (hereafter Pt), are supported on larger particles made of lighter elements, typically carbon [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Contrast variation method applied to structural evaluation of catalysts by X-ray small-angle scattering

Mufundirwa,

Sakurai,

Imai

et al. 2023

Preprint

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In the process of developing carbon-supported metal catalysts, determining the catalyst particle-size distribution is an essential step, because this parameter is directly related to the catalytic activities. The particle-size distribution is most effectively determined by small-angle X-ray scattering (SAXS). When metal catalysts are supported by high-performance mesoporous carbon materials, however, their mesopores may lead to erroneous particle-size estimation if the sizes of the catalysts and mesopores are comparable. Here we propose a novel approach to particle-size determination by introducing contrast variation-SAXS (CV-SAXS). In CV-SAXS, a multi-component sample is immersed in an inert solvent with a density equal to that of one of the components, thereby rendering that particular component invisible to X-rays. We used a mixture of tetrabromoethane and dimethyl sulfoxide as a contrast-matching solvent for carbon. As a test sample, we prepared a mixture of a small amount of platinum (Pt) catalyst and a bulk of mesoporous carbon, and subjected it to SAXS measurement in the absence and presence of the solvent. In the absence of the solvent, the estimated Pt particle size was affected by the mesopores, but in the presence of the solvent, the Pt particle size was correctly estimated in spite of the low Pt content. The results demonstrate that the CV-SAXS technique is useful for correctly determining the particle-size distribution for low-Pt-content catalysts, for which demands are increasing to reduce the use of expensive Pt.

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Section: Introductionmentioning

confidence: 99%

Contrast variation method applied to structural evaluation of catalysts by X-ray small-angle scattering

Mufundirwa,

Sakurai,

Imai

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…Polymer electrolyte fuel cells (PEFCs) efficiently generate a voltage via electrochemical reaction between hydrogen and oxygen, emitting only water and heat as byproducts [1,2]. Consequently, they have huge potential for the decarbonization of e.g.…”

Section: Introductionmentioning

confidence: 99%