Catalyst degradation dissolution rates

With a long period operation, Pt will be gradually dissolved although its dissolution rate is slow, causing degradation of the catalyst s activity. The higher the electrode potential, the faster the electrooxidation rate would be. In a fuel cell, the degradation... 

Halide ions are the most important anion contaminants and may be introduced from the environment or through component materials, such as chlorine used to synthesize catalysts or the fluorine degradation product from the membrane. The presence of halide ions can increase Pt dissolution rates, thereby resulting in reduced lifetimes. 

Lepidocrocite (-y-FeOOH) has also been used as a catalyst for Fentonlike reactions [54]. First-order decomposition of hydrogen peroxide was observed in the presence of this catalyst. Peroxide decay at 20 g/L catalyst was found to be pseudo-first-order and pH-dependent, with rate constant values reported from 0.102 hr-1 at pH 3.3 to 0.326 hr-1 at pH 8.9. In this system benzoic acid degradation was fastest at the low pH value. Under these conditions, acid dissolution of the lepidocrocite was observed to produce... 

The membrane electrode assembly (MEA) is the heart of a fuel cell stack and most likely to ultimately dictate stack life. Recent studies have shown that a considerable part of the cell performance loss is due to the degradation of the catalyst layer, in addition to membrane degradation. The catalyst layer in PEMFCs typically contains platinum/platinum alloy nanoparticles distributed on a catalyst support to enhance the reaction rate, to reach a maximum utilization ratio and to decrease the cost of fuel cells. The carbon-supported Pt nanoparticle (Pt/C) catalysts are the most popular for PEMFCs. Catalyst support corrosion and Pt dissolution/aggregation are considered as the major contributions to the degradation... 

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