Abstract
The influence of loading on the activity and stability of heat-treated carbon-supported cobalt phthalocyanine electrocatalysts for oxygen reduction was studied. The Co loading on the carbon support was varied from 0 to 8 weight percent (w/o), while heat-treatment temperatures ranging from 500 to 1100°C were studied. There is an optimum value of the Co loading on the carbon support (about 3.5 w/o) over which the catalytic activity of the Co on carbon catalyst decreases. This trend is observed in both half-cell (rotating disk electrode measurements) and H2/O2 fuel cell measurements. The optimum value of the Co loading on the carbon support is independent of the heat-treatment temperature. An explanation is proposed for this observation. We have also performed short-term (15 to 18 h) life tests with the 3.5 w/o Co on carbon-sup-port materials heat-treated at various temperatures. It is shown that the current density lost after 18 h of operation is a function of the heat-treatment temperature being lower the higher the temperature. The observed increase in the stability of the material with the heat-treatment temperature is best explained by considering the protective role played by the graphitic-like layer surrounding the Co metal particles.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1162-1168 |
| Number of pages | 7 |
| Journal | Journal of the Electrochemical Society |
| Volume | 142 |
| Issue number | 4 |
| DOIs | |
| State | Published - Apr 1995 |
| Externally published | Yes |
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Electrochemistry
- Materials Chemistry