Tunability of the CO adsorption energy on a Ni/Cu surface: Site change and coverage effects

Abstract

The adsorption energy of carbon monoxide on Ni ad-islands and ultra-thin films grown on the Cu(110) surface can be finely tuned via a complex interplay among diffusion, site change mechanisms, and coverage effects. The observed features of CO desorption can be explained in terms of migration of CO molecules from Cu to Ni islands, competition between bridge and on-top adsorption sites, and repulsive lateral adsorbate-adsorbate interactions. While the CO adsorption energy on clean Cu(110) is of the order of 0.5 eV, Ni-alloying allows for its controlled, continuous tunability in the 0.98-1.15 eV range with Ni coverage. Since CO is a fundamental reactant and intermediate in many heterogeneous catalytic (electro)-conversion reactions, insight into these aspects with atomic level detail provides useful information to potentially drive applicative developments. The tunability range of the CO adsorption energy that we measure is compatible with the already observed tuning of conversion rates by Ni doping of Cu single crystal catalysts for methanol synthesis from a CO, CO, and H stream under ambient pressure conditions.

Tunable Product Selectivity in Electrochemical CO2 Reduction on Well-Mixed Ni–Cu Alloys

“…13,48 If the *CO coverage is considered to be formed from protons in the solution, this depends on both the CO adsorption energy and the CO coverage but not on the hydrogen atom coverage. Generally, the Ni sites disturb the *CO coverage on the copper sites and reduce the availability, 49 which likely explains the reduced selectivity to these products. Interestingly, Cu 0.93 Ni 0.07 represents an exception to this general trend by producing approximately 5.4% more FE for C 2 H 4 at −100 mA cm −2 and has a similar selectivity at −200 mA cm −2 compared to a Cu electrode (Figure 3).…”

Toward Understanding the Kinetics of CO2 Capture on Sodium Carbonate

“…Coverage effects are known to affect the adsorption energy and geometry of gas phase molecules on solid surfaces. , Therefore, three-layer (1 × 2) slab models were used to investigate CO 2 coverage effects (quarter monolayer) on (001) and (−402) facets. To be consistent, H 2 O single adsorption and co-adsorption of H 2 O and CO 2 were carried out on (1 × 2) models as well.…”