Significant modulation of CO adsorption on bimetallic Au19Li cluster

- CO adsorption on all possible sites of various Au19Li clusters is studied.
- Cage-like Au19Li clusters show better propensity to adsorb CO.
- Around 40% enhancement in CO adsorption energy is possible using Li doping in Au20.
- Au19Li clusters may be better catalysts than pure Au20 cluster for CO oxidation.

Adsorption of a CO molecule on various isomers of Au19Li cluster has been investigated within the framework of density functional theory. For a particular isomer, initial geometries of CO adsorbed Au19Li clusters are obtained by placing a CO molecule at each of the non-equivalent positions. It is observed that Li doping can enhance the adsorption energy of CO on Au19Li cluster over that of pure Au20 cluster. Moreover, our study reveals that the endohedrally doped cage-like Au19Li clusters show better propensity to adsorb CO than the corresponding exohedrally doped tetrahedral isomers. Elongation of C-O bond length and the red-shift in C-O stretching frequency have been observed for some of the isomers with high value of adsorption energy including the one with highest value of adsorption energy. Our results indicate that the endohedrally doped cage-like Au19Li clusters may be better catalytic agent than pure Au20 cluster for CO oxidation.