Catalysis by metal nanoparticles supported on functionalized polymers

This contribution is a brief review dealing with metal catalysts prepared on functionalized polymers. The following topics will be touched: i) preparation and properties of metal catalysts based on functionalized polymers; ii) methods for the characterization of these catalysts; iii) effect of mass transport phenomena on the overall rate of a process and on the selectivity in complex reaction systems; iv) deactivation of the polymer-based catalysts; v) applications - selective hydrogenations, one-pot synthesis of methyl isobutyl ketone, removal of nitrates from water. A particular attention is paid to the comparison of polymer-based metal catalysts with those supported on inorganic materials. The mechanical and chemical stability vs. the activity and the cost of the catalysts are discussed. The emphasis will be put on the main advantages of polymer-based catalysts, stemming from easily controlled micro- or macroporous nature and hydrophobic-hydrophilic properties, from the possibility to attach various special functional groups, precise and well defined metal loading and metal distribution in the final catalyst. In the part describing the methods for the characterization of metal polymer-based catalysts, the techniques as evaluation of the mobility on the basis of electron spin resonance and pulse field gradient spin echo NMR will be discussed.