CO Adsorption Phenomena on Metal Surfaces

Carbon monoxide adsorption on metal surfaces underpins a vast array of catalytic and environmental processes, from Fischer–Tropsch synthesis and water–gas shift reactions to pollution control and sensor technologies. Adsorption may occur via physisorption, governed by weak van der Waals forces, or chemisorption, involving the formation of chemical bonds. Preferred adsorption sites include atop, bridge and hollow geometries, whose stability depends on metal crystallography, surface defects and local coordination. Electronic structure descriptors, notably the d-band centre, correlate with adsorption energies and activation barriers, as they reflect the extent of σ-donation from the CO 5σ orbital and π* back-donation into antibonding orbitals. Surface structure sensitivity is exemplified by the enhanced bond weakening and lowered dissociation barriers on stepped or kinked sites compared to flat terraces. Experimental techniques such as infrared spectroscopy, temperature-programmed desorption and scanning tunnelling microscopy, alongside density functional theory, have elucidated the interplay between electronic and geometric factors. Understanding these phenomena at the atomic scale informs the rational design of more active, selective and stable catalysts for energy conversion and environmental remediation.

Research from Nature Portfolio

Recent studies have revealed an entropy-driven phase transition of carbon monoxide on copper surfaces, directly observed by scanning tunnelling microscopy on Cu(111). Complementary first-principles calculations showed that repulsive dipole–dipole interactions between adsorbed CO molecules produce an unexpected transition between a high-density liquid-crystal phase and a low-density crystalline solid. This work provides a unique atomic-scale platform for probing two-dimensional phase behaviour and offers new insights into the thermodynamics that may influence copper-based catalytic oxidation processes.

CO Adsorption Phenomena on Metal Surfaces publication trend

The graph below shows the total number of articles in co adsorption phenomena on metal surfaces across all publications each year (not limited to Nature Index journals).

Technical terms

Chemisorption: Strong adsorption through the formation of chemical bonds between metal surface atoms and the adsorbate.

Physisorption: Weak adsorption dominated by van der Waals interactions without significant bond formation.

d-band centre: Energy-weighted average of a metal’s d-electron density relative to the Fermi level, correlating with adsorbate binding strength.

Back-donation: Transfer of electrons from metal d-orbitals into antibonding orbitals of CO, weakening the C–O bond.

Miller index: Set of integers (hkl) describing the orientation of a crystallographic plane or surface.

References

1. A computational map of the probe CO molecule adsorption and dissociation on transition metal low Miller indices surfaces. Applied Surface Science (2023).
2. Study on the Adsorption Properties and Mechanisms of CO on Nickel Surfaces Based on Density Functional Theory. Energies (2023).
3. Abnormal phase transition between two-dimensional high-density liquid crystal and low-density crystalline solid phases. Nature Communications (2018).
4. Unravelling CO Activation on Flat and Stepped Co Surfaces: A Molecular Orbital Analysis. The Journal of Physical Chemistry C (2024).