Using supported Au nanoparticles as starting material for preparing uniform Au/Pd bimetallic catalysts

Area of Science:

• Materials Science
• Catalysis
• Nanotechnology

Background:

• Producing homogeneous supported bimetallic clusters is challenging.
• The structure and size of metal clusters significantly impact catalytic performance.
• Gold-palladium (AuPd) bimetallic systems are of interest for various catalytic applications.

Purpose of the Study:

• To investigate the role of the gold seed in controlling the structure, size, and catalytic activity of bimetallic AuPd clusters.
• To compare the effects of different gold seed stabilization methods on alloy formation.
• To determine the optimal conditions for preparing uniform AuPd alloy catalysts.

Main Methods:

• Immobilization of protected gold seeds onto activated carbon (AC).
• Addition of palladium to form bimetallic clusters.
• Characterization of cluster structure, composition, and size.
• Evaluation of catalytic activity and selectivity.

Main Results:

• Uniform Au-Pd alloy clusters were obtained using poly(vinyl alcohol) (PVA) as a steric/electrostatic protecting group.
• Gold clusters stabilized with tetrakis(hydroxypropyl)phosphonium chloride (THPC) or no stabilization resulted in inhomogeneous alloys and segregation.
• The uniform alloyed catalyst (Pd@Au(PVA)/AC) exhibited higher activity and selectivity.
• The amount of PVA used was found to be critical for catalyst uniformity, stability, and activity.

Conclusions:

• The choice of gold seed stabilization method is critical for achieving homogeneous bimetallic AuPd alloy clusters.
• Protected gold seeds, particularly with PVA, lead to superior catalytic performance.
• Optimizing the amount of protecting agent (PVA) is essential for developing effective and stable AuPd alloy catalysts.