CO oxidation on h-BN supported Au atom.

Area of Science:

• Materials Science
• Surface Chemistry
• Computational Chemistry

Background:

• Gold (Au) atoms are effective catalysts for CO oxidation.
• Hexagonal boron nitride (h-BN) is a promising support material for catalysts.
• Understanding the role of support defects is crucial for catalyst design.

Purpose of the Study:

• To investigate the mechanism of CO oxidation by O2 on Au atoms supported by pristine and defected h-BN.
• To determine how surface defects (nitrogen and boron vacancies) influence the catalytic properties of supported Au atoms.
• To elucidate the reaction pathways and energy barriers for CO oxidation on these systems.

Main Methods:

• Density Functional Theory (DFT) calculations were employed to study the electronic and catalytic properties.
• Adsorption energies of O2 and CO on Au/h-BN were calculated.
• Reaction pathways and transition states for CO oxidation were identified and characterized.
• Charge transfer analysis was performed to understand electronic interactions.

Main Results:

• Oxygen (O2) binding strength to Au atoms varied depending on the h-BN surface defect.
• Defects like nitrogen vacancies (V(N)@h-BN) enhanced O2 activation due to charge transfer.
• Two distinct CO oxidation pathways were identified: a two-step mechanism and a self-promotion mechanism.
• The interaction between Au and the h-BN support, even when weak, significantly influenced reaction pathways and barriers.

Conclusions:

• The catalytic performance of supported Au atoms is highly sensitive to the nature and presence of defects on the h-BN support.
• Support effects cannot be neglected, even for weak interactions, impacting CO oxidation mechanisms and kinetics.
• Defect engineering of h-BN offers a route to tune the catalytic activity of supported Au for CO oxidation.