Impact of Carbon Support Functionalization on the Electrochemical Stability of Pt Fuel Cell Catalysts
| Autor: | Carsten Cremers, Henrike Schmies, Tilman Jurzinsky, Stefanie Kühl, Peter Strasser, Martin Lerch, Jakub Drnec, Björn Anke, Hong Nhan Nong, Fabio Dionigi, Elisabeth Hornberger |
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| Přispěvatelé: | Publica |
| Rok vydání: | 2018 |
| Předmět: |
Materials science
oxidation General Chemical Engineering chemistry.chemical_element Proton exchange membrane fuel cell 02 engineering and technology Electrolyte 010402 general chemistry Electrochemistry 01 natural sciences Catalysis X-ray photoelectron spectroscopy Materials Chemistry Zeta potential platinum metal nanoparticles Catalysts - Analysis General Chemistry stability 021001 nanoscience & nanotechnology 0104 chemical sciences chemistry Chemical engineering Surface modification 0210 nano-technology Carbon |
| Zdroj: | Chemistry of Materials. 30:7287-7295 |
| ISSN: | 1520-5002 0897-4756 |
| Popis: | Nitrogen-enriched porous carbons have been discussed as supports for Pt nanoparticle catalysts deployed at cathode layers of polymer electrolyte membrane fuel cells (PEMFC). Here, we present an analysis of the chemical process of carbon surface modification using ammonolysis of preoxidized carbon blacks, and correlate their chemical structure with their catalytic activity and stability using in situ analytical techniques. Upon ammonolysis, the support materials were characterized with respect to their elemental composition, the physical surface area, and the surface zeta potential. The nature of the introduced N-functionalities was assessed by X-ray photoelectron spectroscopy. At lower ammonolysis temperatures, pyrrolic-N were invariably the most abundant surface species while at elevated treatment temperatures pyridinic-N prevailed. The corrosion stability under electrochemical conditions was assessed by in situ high-temperature differential electrochemical mass spectroscopy in a single gas diffusion layer electrode; this test revealed exceptional improvements in corrosion resistance for a specific type of nitrogen modification. Finally, Pt nanoparticles were deposited on the modified supports. In situ X-ray scattering techniques (X-ray diffraction and small-angle X-ray scattering) revealed the time evolution of the active Pt phase during accelerated electrochemical stress tests in electrode potential ranges where the catalytic oxygen reduction reaction proceeds. Data suggest that abundance of pyrrolic nitrogen moieties lower carbon corrosion and lead to superior catalyst stability compared to state-of-the-art Pt catalysts. Our study suggests with specific materials science strategies how chemically tailored carbon supports improve the performance of electrode layers in PEMFC devices. |
| Databáze: | OpenAIRE |
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