Theoretical study of CO adsorption on FexCuy (x + y = 3) clusters and reactive activity of their carbonyl complexes

Abstract

In this paper, the adsorption of CO on FexCuy (x + y = 3) clusters was studied by BPW91 method, and all conceivable geometries and electronic states of carbonyl complexes were explored. The results show that bimetallic clusters tend to have higher stepwise CO adsorption energy than corresponding pure clusters, and the adsorption capacity of FeCu2 with CO is substantially larger than that of other carbonyl complexes. The CO bond length and CO stretching indicated that the CO bond is significantly weakened in Fe3(CO)6. In addition, the frontier molecular orbital theory was used to analyze the effect of the second element in the ligand reactions, which also confirmed that the reactions of CO with bimetallic clusters are easier than that of pure cluster systems. Finally, the energy gaps of HOMO and LUMO were used to explore the reactive activity of carbonyl complexes, and it was found that the Fe2Cu(CO)1 has lower energy gap than that of other carbonyl complexes. This suggests that it may be possible to tune bimetallic cluster to get higher activity carbonyl complexes in the reactions.