Theoretical investigation of the adsorption of carbon monoxide on small bimetallic LimCun (m,n ⩽ 4) clusters

A theoretical study was carried out on the adsorption of carbon monoxide on small bimetallic LimCun (m,n ⩽ 4) clusters and it was compared with the adsorption of CO on copper (Cun, n ⩽ 8) clusters using density functional methods. The study of the CO-LimCun system is important to understand the promotion effects of alkali atoms on the copper surface participating in catalytic processes. Adsorption energies for the most stable adsorption systems, ranging from 5.9 to 17.9 kcal/mol were found, which represented very similar values to those calculated for the adsorption of CO on copper clusters in a previous study. Nevertheless, the reactivity of the CO molecule on bimetallic clusters is more favorable in the cases when m < n and CuCu bonds are not broken.