Correlating the Experimentally Determined CO Adsorption Enthalpy with the Electrochemical CO Reduction Performance on Cu Surfaces.

CO binding energy has been widely employed as a descriptor for effective catalysts in the electrochemical CO and CO reduction reactions (CO RR), however, it has yet to be determined experimentally at electrochemical interfaces due to the lack of suitable techniques. In this work, we developed a method to determine the standard adsorption enthalpy of CO on Cu surfaces with quantitative surface enhanced infrared absorption spectroscopy. On dendritic Cu at -0.75 V vs. SHE, the standard adsorption enthalpy, entropy and Gibbs free energy were determined to 1.5±0.5 kJ mol , ≈37.9±13.4 J/(mol K), and ≈-9.8±4.0 kJ mol , respectively. Comparison of the standard adsorption enthalpy of oxide-derived Cu and dendritic Cu, as well as their CORR activities, suggests the presence of stronger binding sites on OD Cu, which could favor multicarbon products. The method developed in this work will help establish the correlation between the CO binding energy and the CO RR activity.