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 been applied to the electrocatalytic hydrogenation of organic substates containing two different carbon-carbon double bonds, namely limonene and carvone. Results demonstrated that some regioselectivity was achieved according to the metal catalyst incorporated in the polymeric matrix. In addition, highly active cathodes for the hydrogenation of carvone to the doubly reduced carvomenthone were synthesized by dispersing a bimetallic catalyst (Pd + Pt or Pd + Rh) in the polymer film, while neither monometallic catalyst was able to achieve efficiently this hydrogenation. Auger electron spectroscopy (AES) depth profile analysis of two-component catalytic films showed that the two metal catalysts were dispersed throughout the polymer layer and gave information on their relative concentrations.