Adsorption-induced structural changes of gold cations from two- to three-dimensions

Area of Science:

• Computational Chemistry
• Materials Science
• Nanocatalysis

Background:

• Gold clusters are crucial for developing active nanocatalysts.
• Understanding their geometry, especially with adsorbates, is key to catalyst design.
• Previous studies highlight the sensitivity of gold cluster properties to size and composition.

Purpose of the Study:

• To theoretically investigate the geometry structures of bare and CO-saturated gold cationic clusters (Au(n)(+), n=4-6).
• To analyze the impact of carbon monoxide (CO) chemisorption on gold cluster dimensionality and electronic structure.
• To evaluate the accuracy of density functional theory (DFT) methods for predicting cluster structures and energies.

Main Methods:

• Detailed theoretical calculations using density functional theory (DFT).
• Analysis of geometry optimizations for bare and CO-adsorbed Au(n)(+) clusters.
• Investigation of electronic structures and binding sites of gold clusters and their complexes.

Main Results:

• CO chemisorption induces significant structural transitions from 2D to 3D geometries in Au(n)(+) clusters, even for n=4.
• Gold cationic clusters with adsorbed CO exhibit unique coordination binding sites and distinct electronic properties.
• Standard DFT methods show strong dependence on exchange-correlation functionals for accurate energy predictions of isomers and complexes.

Conclusions:

• CO adsorption fundamentally alters the dimensionality and electronic nature of small gold clusters.
• The findings provide insights into designing gold-based nanocatalysts with tailored properties.
• Caution is advised when using DFT as a black box; method selection is critical for reliable predictions of gold cluster systems.