Alloying in Cu/Pd nanoparticle catalysts

In this paper we show a new application of the atomic layer epitaxy techniq ue to prepare binary alloy nanoparticle catalysts on various supports. The technique is used to prepare Cu/Pd bimetallic catalysts on SiO2 and on gamm a-Al2O3. The samples were characterized by means of transmission electron m icroscopy (TEM) and extended X-ray absorption fine structure (EXAFS) measur ements. The EXAFS results show alloying in the Cu/Pd samples with a Cu-rich surface for the alumina-supported sample and random alloying for the silic a-supported sample. From TEM and EXAFS measurements the particle sizes are determined to be in the range 20-60 Angstrom.