Catalysis continued catalyst poisoning

Poisoning of platinum fuel cell catalysts by CO is undoubtedly one of the most severe problems in fuel cell anode catalysis. As shown in Fig. 6.1, CO is a strongly bonded intermediate in methanol (and ethanol) oxidation. It is also a side product in the reformation of hydrocarbons to hydrogen and carbon dioxide, and as such blocks platinum sites for hydrogen oxidation. Not surprisingly, CO electrooxidation is one of the most intensively smdied electrocatalytic reactions, and there is a continued search for CO-tolerant anode materials that are able to either bind CO weakly but still oxidize hydrogen, or that oxidize CO at significantly reduced overpotential. 

From the standpoint of daily capacity, the greatest application of fluidized bed catalysis is to the cracking of petroleum fractions into the gasoline range. In this process the catalyst deactivates in a few minutes, so that advantage is taken of the mobihty of fluidized catalyst to transport it continuously between reaction and regeneration zones in order to maintain its activity some catalyst also must be bled off continuously to maintain permanent poisons such as heavy metal deposits at an acceptable level. 

An optimum of 2 kg of the corresponding amine could be synthesized using 1 g Pd in ethanol/water without catalyst regeneration. Therewith, it was shown that continuous-flow analysis allows a fast optimization of various aspects of heterogeneous catalysis and synthesis routes, such as solvent effects, competitive adsorption, and irreversible poisoning. 

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