Novel phenomenon of enhancement of IR absorption of CO adsorbed on nanoparticles of Pd confined in supercages of Y-zeolite

Nanoparticles of palladium were synthesized by a 'ship-in-a-bottle' techniq ue in supercages of Y-zeolite. The ions of Pd2+ were introduced into the ze olite by ionexchange between PdCl2 and NaY zeolite. They were then reduced by an electrochemical method and assembled to form nanoparticals by admissi on and release of CO. The electrode of palladium-loading zeolite film was c haracterized by cyclic voltammetry, and the adsorption of carbon monoxide o n the electrode was studied using in situ electrochemical FTIR reflection s pectroscopy. A novel phenomenon of enhanced IR absorption (EIRA) was observ ed for the first time. In comparison with CO adsorbed on a massive I'd elec trode, the IR absorption of CO adsorbed on nanoparticles of Pd confined in supercages of Y-zeolite has been enhanced to about 51 times. (C) 2001 Publi shed by Elsevier Science B.V.