Intermetallic compound nanoparticles dispersed on the surface of oxide support as active and selective catalysts

Abstract

Preparation of nanoparticles of intermetallic compounds and their application to various catalytic reactions are summarized. On the surface of silica support, single-phase nanoparticles of intermetallics with various combinations of elements were obtained by co-impregnation and/or successive impregnation procedures. On alumina support, its strong interaction with metal species requires another preparation procedure, liquidphase reduction, to obtain intermetallic nanoparticles with high phase purity. Most of the particles formed on both supports had diameters of 3∼20 nm. Thus prepared intermetallic nanoparticles were used as catalysts for various reactions such as H 2 -D 2 equilibration, selective hydrogenation, dehydrogenation, oxidation and isomerization. The catalytic activity and selectivity of nanoparticles differed from each other depending on the combination and composition of two elements. In some cases, the intermetallic catalysts gave much higher activity and/or selectivity than their component monometallic catalysts. The unique catalytic properties of intermetallic compounds were discussed in terms of the electronic and geometric factors compared with pure metals.