Selective Orbital Coupling: An Adsorption Mechanism in Single-Atom Catalysis

Area of Science:

• Materials Science
• Catalysis
• Surface Chemistry

Background:

• Quantitative understanding of chemisorption on single-atom catalysts (SACs) is crucial for catalyst design.
• The underlying physical mechanism of chemisorption on SACs remains under debate.
• Electronic properties are key to understanding and designing effective SACs.

Purpose of the Study:

• To explore the correlations between electronic structure characteristics and chemisorption on SACs.
• To investigate the CO catalytic oxidation on single transition metal dopants as a theoretical model.
• To elucidate the fundamental adsorption mechanism in SAC systems.

Main Methods:

• Theoretical modeling of CO catalytic oxidation on single transition metal dopants (Sc, Ti, V, Cr, Mn, Fe, Co, Ni).
• Analysis of atomic d-orbital interactions with the adsorbed O2 π* orbital.
• Investigation of electronic metal-support interactions and their role in M-O bonding.

Main Results:

• Identified selective orbital coupling between metal d-orbitals and the O2 π* orbital.
• Demonstrated that the alignment between selected d-states and the π* state determines bond strength, irrespective of electron occupation.
• Showed that electron transfer for M-O bonding can be facilitated by the support via electronic metal-support interactions.

Conclusions:

• The chemisorption mechanism in SACs arises from the interplay between localized metal d-orbitals and the continuous energy band of the support (e.g., Au).
• Selective orbital coupling provides a fundamental framework for understanding adsorption strength and reaction barriers in SACs.
• This work offers insights into rational catalyst design by focusing on electronic structure alignment for enhanced chemisorption.