Catalyst ageing fuel cells

However, in the case of multimetallic catalysts, the problem of the stability of the surface layer is cmcial. Preferential dissolution of one metal is possible, leading to a modification of the nature and therefore the properties of the electrocatalyst. Changes in the size and crystal structure of nanoparticles are also possible, and should be checked. All these problems of ageing are crucial for applications in fuel cells. 

Figure 61. Tailpipe emission of CO, HC and NO c from a gasoline fueled passenger car equipped with a three-way catalytic converter, in the US-FTP 75 vehicle test, as a function of the number of catalysts in the converter at fixed total catalyst volume (monolith catalyst with 62 cells cm three-way formulation with Pt 0.83gl , Rh 0.16gl fresh condition and after high temperature aging for 20 hours on an engine bench).

A fuel cell decays with time, and the rate of decay determines its durability. The decay is related to the aging of the fuel cell components, especially the membrane electrolyte, the catalysts, and the catalyst support. The decay of the membrane will cause its thinning and mechanical property deterioration. The loss of its mechanical properties often causes a fuel cell to fail prematurely and catastrophically. The decay of the catalyst is normally due to the particle size increase and the particle dissolution and redistribution. Catalyst decay rarely causes a sudden failure of a cell. The decay of the catalyst-support is often related to its corrosion. Corrosion makes the electrode more prone to flooding and accelerates the growth and redistribution of the catalyst particles. 

For fuel cell testing at 150 °C, the performance degradation of the MEA made from the PtZr02/C catalyst, after 3000 cycles of aging, is less significant than that... 

Catalyst ageing and degradation in polymer electrolyte membrane fuel cells... 

Malek, K. Franco, A. A. Microstructure-based modeling of aging mechanisms in catalyst layers of polymer electrolyte fuel cells. J. Phys. Chem. B 115 (2011), pp. 8088-8101. 

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