Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4767536 | Electrochimica Acta | 2017 | 8 Pages |
Abstract
Optimizing the catalyst layer structure is one of the key issues for improving performance despite lower platinum loading. The catalyst ink, consisting of platinum-loaded carbon particles and ionomer dispersed in an aqueous solvent, is a key factor for controlling the structure of the catalyst layer because the catalyst layer is prepared in a wet coating process. For that purpose, we visualized the nanostructure of the ionomer in the catalyst ink by cryogenic electron microscopy, especially cryogenic transmission electron microscopy (cryo-TEM). By cryo-TEM, it was revealed that ionomer molecules formed rod-like aggregates macro-homogeneously in the solvent, and a similar morphology was observed in a carbon-particle-containing solvent. In contrast, ionomer aggregates in the catalyst ink containing platinum nanoparticles loaded on carbon particles were denser in the vicinity of the platinum-loaded carbon particles. That can be attributed to strong interaction between platinum nanoparticles and sulfonic acid groups in the ionomer. It also implies that a good understanding of ionomer morphology in the catalyst ink can play an important role in controlling the catalyst layer microstructure for reducing platinum loading.
Keywords
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Chemical Engineering (General)
Authors
Shinichi Takahashi, Junichi Shimanuki, Tetsuya Mashio, Atsushi Ohma, Hajime Tohma, Ayumi Ishihara, Yoshiko Ito, Yuri Nishino, Atsuo Miyazawa,