Kinetic Study of CO Desorption from PtRu/C PEM Fuel Cell Anodes - Temperature Dependence and Associated Microstructural Transformations

摘要

The temperature dependence of the CO desorption process on a carbon supported platinum-ruthenium alloy catalyst has been investigated using isotopic exchange experiments. The kinetics of CO desorption on PtRu/C catalyst have been studied as a function of temperature and flow rate. Desorption rate constants have been determined for a temperature range between 25°C and 150°C. All PtRu/C results have been compared with those obtained for the Pt/C catalyst under similar experimental conditions. Quite different desorption rate constants have been observed. The variation in apparent Arrhenius parameters (frequency factor A and activation energy Ea) for PtRu/C and Pt/C could possibly explain their different degrees of poisoning by CO in Proton Exchange Membrane Fuel Cells (PEMFC) and the underlying adsorption/desorption processes. The effect of temperature treatment on the PtRu/C catalyst properties has also been investigated with respect to CO desorption kinetics and to the associated microstructural transformations.