Selective oxidation with dioxygen by gold nanoparticle catalysts derived from 55-atom clusters

Area of Science:

• Nanomaterials Science
• Catalysis
• Surface Chemistry

Background:

• Supported gold nanoparticles exhibit unique catalytic properties, but their origin remains unclear.
• Previous studies identified a size threshold (~3.5 nm) for gold nanoparticles on TiO2, potentially linked to a metal-to-insulator transition.
• The role of support interactions in gold nanoparticle catalysis is complex and not fully understood, especially for selective oxidation reactions.

Purpose of the Study:

• To investigate the catalytic activity of very small gold entities derived from 55-atom gold clusters.
• To determine the size-dependent catalytic behavior of gold nanoparticles on inert supports for selective styrene oxidation.
• To elucidate the intrinsic factors governing the catalytic efficiency of gold nanoparticles.

Main Methods:

• Synthesis of 1.4 nm gold entities from 55-atom gold clusters supported on inert materials.
• Catalytic testing of these gold entities for the selective oxidation of styrene using dioxygen.
• Systematic variation of gold particle size to identify activity thresholds.

Main Results:

• Gold entities derived from 55-atom clusters (approx. 1.4 nm) demonstrated efficient and robust catalysis for selective styrene oxidation.
• A sharp catalytic activity threshold was observed, with particles approximately 2 nm and larger being inactive.
• The findings indicate that intrinsic electronic structure changes in small gold nanoparticles are responsible for their catalytic activity.

Conclusions:

• Very small gold nanoparticles, synthesized from 55-atom clusters, are effective catalysts for selective styrene oxidation.
• Catalytic activity is strongly dependent on particle size, with a critical threshold below 2 nm.
• The intrinsic electronic properties of small gold nanoparticles, rather than support interactions, are the primary drivers of their catalytic performance, offering a viable route for practical catalyst synthesis.