The curious case of CO$_2$ dissociation on Cu(110)

TL;DR

This study challenges previous assumptions by measuring CO$_2$ dissociation probabilities on Cu(110), revealing higher energy barriers and lower dissociation rates than previously thought, which impacts understanding of catalytic CO$_2$ conversion.

Contribution

It provides new experimental measurements of CO$_2$ dissociation on Cu(110), suggesting significantly higher energy barriers than earlier studies and prompting reevaluation of catalytic mechanisms.

Findings

Measured dissociation probabilities range from 3.9×10⁻⁴ to 1.8×10⁻².

Estimated dissociation barrier is around 2.0 eV, higher than prior estimates.

Results indicate a need to reconsider elementary steps in CO$_2$ reduction on copper surfaces.

Abstract

Dissociation of CO$_2$ on copper surfaces, a model system for understanding the elementary steps in catalytic conversion of CO$_2$ to methanol has been extensively studied in the past. It is thought to be reasonably well-understood from both experiments and theory. In contrast, our findings reported here suggest a different picture. Using molecular beam surface scattering methods, we measure the initial dissociation probabilities ($S_{\rm 0}$) of CO$_2$ on a flat, clean Cu(110) surface under ultra-high vacuum conditions. The observed $S_{\rm 0}$ ranges from $3.9\times10^{-4}$ to $1.8\times10^{-2}$ at incidence energies of 0.64 eV to 1.59 eV with a lower limit to dissociation barrier estimated to be around 2.0 eV, much larger than that understood previously. We discuss the possible reasons behind such large differences in our results and previous work. These findings are anticipated to be extremely important for obtaining a correct understanding of elementary steps in CO$_2$ dissociation on Cu surfaces.