Feed gas exchange (startup/shutdown) effects on Pt/C cathode electrocatalysis and surface Pt-oxide behavior in polymer electrolyte fuel cells as revealed using in situ real-time XAFS and high-resolution STEM measurements
| Autor: | Kotaro Higashi, Yasuhiro Iwasawa, Takuma Kaneko, Tomoya Uruga, Gabor Samjeské, Takao Gunji, Mizuki Tada |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
In situ
Materials science Membrane electrode assembly Oxide General Physics and Astronomy Nanoparticle 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Electrocatalyst Electrochemistry 01 natural sciences Cathode 0104 chemical sciences law.invention X-ray absorption fine structure chemistry.chemical_compound Chemical engineering chemistry law Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | Physical chemistry chemical physics : PCCP. 22(17) |
| ISSN: | 1463-9084 |
| Popis: | The synchronizing measurements of both cyclic voltammograms (CVs) and real-time quick XAFSs (QXAFSs) for Pt/C cathode electrocatalysts in a membrane electrode assembly (MEA) of polymer electrolyte fuel cells (PEFCs) treated by anode-gas exchange (AGEX) and cathode-gas exchange (CGEX) cycles (startup/shutdown conditions of FC vehicles) were performed for the first time to understand the opposite effects of the AGEX and CGEX treatments on the Pt/C performance and durability and also the contradiction between the electrochemical active surface area (ECSA) decrease and the performance increase by CGEX treatment. While the AGEX treatment decreased both the ECSA and performance of MEA Pt/C due to carbon corrosion, it was found that the CGEX treatment decreased the ECSA but increased the Pt/C performance significantly due to high-index (331) facet formation (high-resolution STEM) and hence the suppression of strongly bound Pt-oxide formation at cathode Pt nanoparticle surfaces. Transient QXAFS time-profile analysis for the MEA Pt/C also revealed a direct relationship between the electrochemical performance or durability and transient kinetics of the Pt/C cathode. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|