Tunable activity of electrocatalytic CO dimerization on strained Cu surfaces: Insights from ab initio molecular dynamics simulations

Abstract

Controlling catalytic activities through surface strain engineering remains a hot topic in electrocatalysis studies. Herein, ab initio molecular dynamics (AIMD) simulation associated with free energy sampling technology were performed to study the energetics of the key step of producing C2 products in electrocatalytic reduction of CO or CO2, i.e. CO dimerization, on strained Cu(100) with an explicit aqueous solvent model. It is worth mentioning that when compressive strain reaches a certain extent, the surface of Cu(100) will undergo reconstruction. We showed that, from tensile to compressive strain, the free energy barrier of CO dimerization decreased, suggesting that the activity of CO dimerization increases. It was also found that some of the reconstructed surfaces showing the lowest free energy barriers but might be less stable can be stabilized in the presence of adsorbed O or CO. Upon detailed quantitative analysis on the charges of surface Cu atoms, we found that the free energy barriers were strongly correlated with the charge of Cu atoms where the OCCO intermediate adsorbs. When the surfaces structures of Cu(100) were altered under compressive strain, the electronic structure of surface Cu atoms was monitored and thus the activity of electrocatalytic CO dimerization can be tuned.