A comparative study of CO adsorption on flat, stepped and kinked Au surfaces using density functional theory

TL;DR

This study uses density functional theory to compare CO adsorption energies on various gold surfaces, revealing how local atomic coordination influences binding strength and how coverage affects adsorption.

Contribution

It provides a detailed comparison of CO adsorption on flat, stepped, and kinked gold surfaces, highlighting the role of atomic coordination and coverage effects.

Findings

Lower coordination sites have higher binding energies.

Increased CO coverage decreases adsorption energy.

Work-function and vibrational frequency changes depend on coverage.

Abstract

Our ab initio calculations of CO adsorption energies on low miller index (111), (100), stepped (211), and kinked (532) gold surfaces show a strong dependence on local coordination with a reduction in Au atom coordination leading to higher binding energies. We find trends in adsorption energies to be similar to those reported in experiments and calculations for other metal surfaces. The (532) surface provides insights into these trends because of the availability of a large number of kink sites which naturally have the lowest coordination (6). We also find that, for all surfaces, an increase in CO coverage triggers a decrease in the adsorption energy. Changes in the work-function upon CO adsorption, as well as the frequencies of the CO vibrational modes are calculated, and their coverage dependence is reported.