Density functional study of CO adsorption on Sc(n) (n=2-13) clusters

Area of Science:

• Materials Science
• Surface Science
• Computational Chemistry

Background:

• Understanding molecule-surface interactions is crucial for catalysis and materials design.
• Scandium clusters are promising for various applications due to their unique electronic and magnetic properties.

Purpose of the Study:

• To investigate the adsorption patterns and properties of a single carbon monoxide (CO) molecule on small scandium (Sc) clusters (Sc(n), n=2-13).
• To explore the influence of cluster size and adsorption site on CO binding energy, electronic structure, and magnetic properties.

Main Methods:

• Density Functional Theory (DFT) calculations using the generalized gradient approximation (GGA) were employed.
• Analysis of adsorption energy, bond lengths, vibrational frequencies, charge transfer, and magnetic moments.

Main Results:

• Two distinct adsorption patterns were identified: CO binding to hollow sites (Pattern a) or bridge sites (Pattern b), with the latter significantly lengthening Sc-Sc bonds.
• Adsorption energy, C-O bond length, vibrational frequency, and charge transfer exhibited size-dependent variations and odd-even oscillations, peaking at n=5, 7, and 9, indicating high chemical reactivity.
• Magnetic properties of Sc clusters were largely retained upon CO adsorption, except for specific sizes (n=2, 4, 12, 13), with significant magnetic moment reduction observed for Sc(13).

Conclusions:

• The adsorption behavior of CO on Sc clusters is governed by cluster size, adsorption site, and the intrinsic stability of the bare clusters.
• CO adsorption significantly impacts the electronic and magnetic properties of Sc clusters, suggesting potential for tuning these properties through controlled adsorption.
• Scandium clusters with specific sizes (e.g., n=5, 7, 9) show enhanced reactivity towards CO adsorption, making them attractive candidates for catalytic applications.