Investigation of Tetraalkylammonium Bromide Stabilized Palladium/Platinum Bimetallic Clusters Using Extended X-ray Absorption Fine Structure Spectroscopy

Abstract

Structural investigations using EXAFS spectroscopy and standard analytical methods were performed on electrochemically synthesized tetrabutylammonium bromide stabilized Pd/Pt bimetallic clusters with different Pd/Pt ratios. The results of these investigations allow the determination of a detailed model concerning the structure of these 3.5 nm sized bimetallic clusters. The cores of the clusters are enriched in platinum metal, while the outer shell is enriched in palladium metal. The nanostructured particles are partially oxidized. The amounts of oxide in the outer shells are larger than in the cores of the clusters. Also, a small amount of the metal is present as metal bromide. The ammonium salt stabilizer forms a protective layer around the cluster.