Effect of Ligand Attachment at Ag for CO Oxidation: A Computational Investigation.

Heterogeneous CO oxidation is a demanding reaction at room temperature due to the high activation energy required to break the O=O bond. While several metal clusters are reported to oxidize CO successfully, they fall short of their selectivity for the reaction and recyclability. In this regard, there is a need for economic catalysts with high catalytic activity, low activation barrier, and reusability. In this study, we have investigated the catalytic activity of the neutral pristine and ligated Ag cluster toward CO oxidation. We investigated the attachment effect of three organic donor ligands: trimethylphosphine, triethylphosphine, and -ethyl pyrrolidone to the Ag cluster. Our results show that including donor ligands on the Ag cluster surface can significantly reduce the barrier heights for CO oxidation. The minimum barrier heights with the system coordinated with triethylphosphine showed the lowest activation barrier of 1.06 kcal/mol compared to the high activation barrier of 14.77 kcal/mol recorded for the pristine cluster. Exploration of the reaction mechanism and charge analysis showed that the electron donor ligands activate O via charge donation, thereby reducing the barrier heights of CO oxidation.