Synergistically Activated Pd Atom in Polymer-Stabilized Au₂₃Pd₁ Cluster

Area of Science:

• Nanocatalysis
• Materials Science
• Heterogeneous Catalysis

Background:

• Gold clusters are promising catalysts but often require doping to enhance activity.
• Polyvinylpyrrolidone (PVP) is a common stabilizer for metal nanoparticles.
• Understanding the role of dopant atoms in cluster catalysis is crucial for designing efficient catalysts.

Purpose of the Study:

• To synthesize and characterize single palladium atom doped gold clusters (Au23Pd1:PVP).
• To investigate the geometric structure and surface exposure of the doped clusters.
• To evaluate the catalytic performance of Au23Pd1:PVP in aerobic oxidation reactions and compare it with undoped clusters.

Main Methods:

• Kinetically controlled coreduction for selective synthesis.
• Density functional theory (DFT) calculations for structural analysis.
• Aberration-corrected transmission electron microscopy (TEM) and extended X-ray absorption fine structure (EXAFS) for structural determination.
• Fourier transform infrared spectroscopy (FTIR) for surface analysis.
• Catalytic testing for aerobic oxidation of benzyl alcohols.

Main Results:

• Au23Pd1:PVP clusters were successfully synthesized with PVP stabilization.
• DFT and experimental results confirmed similar atomic arrangements to Au24:PVP but with all atoms, including Pd, exposed on the surface.
• Au23Pd1:PVP demonstrated significantly higher catalytic activity than Au24:PVP for aerobic oxidation of p-substituted benzyl alcohols.
• Kinetic studies revealed that hydride abstraction is the rate-determining step, with lower activation energy for the doped clusters.

Conclusions:

• Single Pd atom doping in Au23 clusters effectively enhances catalytic activity for aerobic alcohol oxidation.
• The exposed Pd atom in Au23Pd1:PVP acts as the primary active site, lowering the activation energy barrier.
• This study highlights the potential of single-atom doping in gold clusters for developing advanced nanocatalysts.