Synergistically Activated Pd Atom in Polymer-Stabilized Au 23 Pd 1 Cluster.

Single Pd atom doped Au 23 Pd 1 clusters stabilized by polyvinylpyrrolidone (Au 23 Pd 1 :PVP) were selectively synthesized by kinetically controlled coreduction of the Au and Pd precursor ions. The geometric structure of Au 23 Pd 1 :PVP was investigated by density functional theory calculation, aberration-corrected transmission electron microscopy, extended X-ray absorption fine structure analysis, Fourier transform infrared spectroscopy of adsorbed CO, and hydrogenation catalysis. These results showed that Au 23 Pd 1 :PVP takes polydisperse but the same atomic arrangements as undoped Au 24 :PVP while exposing all the atoms including the Pd atom on the surface. Au 23 Pd 1 :PVP exhibited a significantly higher catalytic activity than Au 24 :PVP for the aerobic oxidation of p -substituted benzyl alcohols. The kinetic studies showed that the rate-determining step was the hydride abstraction from the α-carbon of the alkoxides for both systems. The activation energy for hydride abstraction by Au 23 Pd 1 :PVP was lower than that by Au 24 :PVP, indicating that the doped Pd atom acts as the active center.