Oxygen electroreduction catalyzed by gold nanoclusters: strong core size effects

Area of Science:

• Nanotechnology
• Electrochemistry
• Materials Science

Background:

• Gold nanoclusters (Au NCs) are investigated for catalytic applications.
• Understanding the relationship between size and catalytic activity is crucial.

Purpose of the Study:

• To investigate the effect of gold nanocluster core size on electrocatalytic activity for oxygen reduction.
• To elucidate the underlying mechanisms responsible for size-dependent activity.

Main Methods:

• Electrochemical characterization of gold nanoclusters with varying core sizes (e.g., Au(140) to Au(11)).
• Analysis of key electrochemical parameters like onset potential (Eonset) and peak current density (JK).

Main Results:

• A decrease in gold nanocluster core size from Au(140) to Au(11) significantly enhanced electrocatalytic activity for oxygen reduction.
• Smaller clusters exhibited a more favorable onset potential and higher peak current density.
• Increased fraction of low-coordination surface atoms and a shift of the d-band center towards the Fermi level were observed with decreasing size.

Conclusions:

• Gold nanocluster size is a critical factor in optimizing electrocatalytic activity for oxygen reduction.
• Smaller gold nanoclusters offer superior performance due to altered surface atom characteristics and electronic properties facilitating oxygen adsorption.