Thermal Stability in Air of Pt/C Catalysts and PEM Fuel Cell Catalyst Layers
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- 作者：Olga A. Baturina ; Steven R. Aubuchon ; and Kenneth J. Wynne
- 刊名：Chemistry of Materials
- 出版年：2006
- 出版时间：March 21, 2006
- 年：2006
- 卷：18
- 期：6
- 页码：1498 - 1504
- 全文大小：214K
- 年卷期：v.18,no.6(March 21, 2006)
- ISSN：1520-5002
文摘
The durability of PEM fuel cell materials is essential to application longevity. This research exploresthe limits of thermal stability of platinum/Vulcan XC 72 catalysts and a 46 wt % Pt/Vulcan XC 72/Nafion catalyst layer. The thermal stability of Pt/Vulcan XC 72 catalysts and the PEM fuel cell catalystlayer is studied by thermal gravimetric analysis (TGA) in air. The products of decomposition are analyzedwith TGA coupled with mass spectrometry (TGA-MS). Low temperature (100-200 
C) carboncombustion in the presence of platinum is confirmed. The high precision and sensitivity of TGA allowsdifferentiation of two oxidative/mass loss regimes for 46% Pt/C. The presence of surface protective groupsraises the activation energy for the low-temperature/low-conversion (
5%) oxidation of 46% Pt/VulcanXC 72 (197 ± 13 kJ/mol) compared to a higher temperature/higher conversion level (10-30%) process(140 ± 10 kJ/mol). In PEM fuel cell catalyst layers, the thermal decomposition temperature of Nafionis lowered by about 100 C to 300 C in the presence of Pt/C catalysts. As a result of the above studiesit was found that TGA is convenient for the determination of Pt wt % in catalyst-coated membranes.
C) carboncombustion in the presence of platinum is confirmed. The high precision and sensitivity of TGA allowsdifferentiation of two oxidative/mass loss regimes for 46% Pt/C. The presence of surface protective groupsraises the activation energy for the low-temperature/low-conversion (5%) oxidation of 46% Pt/VulcanXC 72 (197 ± 13 kJ/mol) compared to a higher temperature/higher conversion level (10-30%) process(140 ± 10 kJ/mol). In PEM fuel cell catalyst layers, the thermal decomposition temperature of Nafionis lowered by about 100 C to 300 C in the presence of Pt/C catalysts. As a result of the above studiesit was found that TGA is convenient for the determination of Pt wt % in catalyst-coated membranes.