CATALYTIC PROPERTIES OF Pd_xZn_(1-x) NANOPARTICLES PREPARED BY POLYOL METHOD IN SELECTIVE HYDROGENATION OF 2-METHYL-3-BUTYN-2-OL

摘要

Highly dispersed polymer-protected Pd/Zn bimetallic nanoclusters with the composition ranging from 1/9 to 6/1 have been obtained by an polyol reduction method. High resolution transition electron microscopy results show different PdZn bimetallic structures having reproducible narrow distribution of particle sizes and average particle diameter of about 2 nm. These bimetallic nanoclusters were used as prepared and after embedding in a titania matrix for selective hydrogenation of 2-methyl-3-butyn-2-ol. Their catalytic activity and selectivity are demonstrated to be dependent on the metal composition. The effect of the particle composition is different for the colloidal and embedded particles. A monometallic Pd colloid shows the highest activity and selectivity. Among supported catalysts, the highest selectivity can be achieved for an embedded bimetallic nanocluster with a molar ratio of Pd/Zn= 2/1.