ELECTROCATALYTIC HYDROGENATION ON NOBLE-METAL PARTICLES DISPERSED IN POLYMER-FILMS - ENHANCED CATALYTIC ACTIVITY-INDUCED BY THE INCORPORATION OF BIMETALLIC CATALYSTS

Zerovalent palladium, platinum and rhodium catalysts dispersed in thin poly(pyrrole-alkylammonium) films coated on carbon electrodes have be en applied to the electrocatalytic hydrogenation of organic substates containing two different carbon-carbon double bonds, namely limonene a nd carvone. Results demonstrated that some regioselectivity was achiev ed according to the metal catalyst incorporated in the polymeric matri x. In addition, highly active cathodes for the hydrogenation of carvon e to the doubly reduced carvomenthone were synthesized by dispersing a bimetallic catalyst (Pd + Pt or Pd + Rh) in the polymer film, while n either monometallic catalyst was able to achieve efficiently this hydr ogenation. Auger electron spectroscopy (AES) depth profile analysis of two-component catalytic films showed that the two metal catalysts wer e dispersed throughout the polymer layer and gave information on their relative concentrations.