Metal ionomers catalytic reactions

Reactions of Potential Catalytic Interest Transition Metal Ionomers... 

As indicated in the previous section, a range of reactions of transition metal ionomers of potential catalytic interest have been studied (14-23). While space does not permit presenting the results in detail here, it is appropriate to illustrate several of the types of results that have been obtained. The first involves reactions that can be compared readily to reactions of the same metals or ions on other supports. The second type demonstrates the formation of metal particles by reduction of metal ionomers. And, the third type concerns the catalytic potential of these types of systems. 

Finally, several of the metal ionomer systems have been tested for their catalytic activity (17,22,23). These studies, also, are too extensive to detail here, but several results can be stated. Of particular importance, the reduced RuPFSA, RhPFSA and PtPFSA materials catalyze the oxidation of CO effectively. The order of CO oxidation rates is RuPFSA > RhPFSA > PtPFSA. The rate of the 2CO/O0 reaction is significantly lower with PtPFSA than it is with RuPFSA and RhPFSA, but its activation energy with PtPFSA is similar to that calculated for known Si02 Pt catalysts. The fact that the rates and apparent activation energies for the reactions carried out with reduced RhPFSA and RuPFSA are lower than those over SiC -supported catalysts shows that the reactions are gas diffusion limited. 

The study of chemistry in ionomers will be illustrated in three ways. The first involves several feasibility studies, specifically the reactions of metal ions with simple gaseous molecules. The second involves results of studies of systems of potential catalytic importance. And, the third illustrates the study of particle formation and reaction kinetics. They are illustrative of a body of work in this area (14-18). 

Catalysis or Catalytic Supports, lonomers have been used as catalysts. Perfiuorosulfonated ionomers have been used as superacid catalysts in various reactions (214-216). In addition, the ionic aggregates can serve as microreactors, implying a wide range of potential applications in this area. Thus, active ions or metals in the phase-separated regions of the ionomer can be used as catalysts (206). For example, when various gases are catalyzed by cations in the multiplets, amines, hydrides, and carbonyls are formed (206,217,218). The cations in the multiplets can also be reduced, and converted to metallic particles which can also act as catalysts (219-225). 

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