CO oxidation catalysed by Pd-based bimetallic nanoalloys.

Area of Science:

• Computational chemistry and materials science
• Surface science and catalysis
• Nanotechnology and materials engineering

Background:

• Catalytic efficiency of palladium (Pd)-based nanoalloys for CO oxidation is critical.
• Understanding the role of cluster geometry in reaction mechanisms is essential for catalyst design.
• Density functional theory (DFT) is a key tool for investigating catalytic processes at the atomic level.

Purpose of the Study:

• To investigate the influence of catalytic cluster geometry on energy barriers for CO oxidation over Pd-based bimetallic nanoalloys.
• To explore how geometric changes in reaction intermediates affect catalytic activity.
• To demonstrate the potential for fine-tuning nanoalloy properties through compositional adjustments.

Main Methods:

• Global geometry optimization using Density Functional Theory (DFT).
• Simulation of CO oxidation reaction pathways over Pd-based bimetallic nanoalloy clusters.
• Analysis of energy barriers and geometric configurations of reaction intermediates.

Main Results:

• Dramatic geometry changes between intermediates can significantly increase energy barriers, hindering catalysis.
• Substitution of a Pd atom with Ag in a Pd5 cluster (forming Pd4Ag1) shows potential for improved catalytic properties.
• Substitution with Au did not enhance catalytic properties due to weaker metal-adsorbate hybridization.

Conclusions:

• Catalyst cluster geometry is a crucial factor determining energy barriers in CO oxidation.
• Controlling cluster geometry through metal mixing in nanoalloys offers a route to design efficient catalysts.
• DFT methods require careful selection of geometric configurations for accurate reaction path descriptions.