Ab Initio Investigation on the Role of Ligation of Metal Chalcogenide Clusters for CO Oxidation

This computational study shows that partial ligation of metal chalcogenide clusters can lead to a class of catalysts with low oxidation barriers for CO oxidation. Two metal chalcogenide clusters, W₆Se₈ and Mo₆Te₈, were investigated for their catalytic activity toward CO oxidation, a crucial reaction with substantial environmental and industrial implications. Bare clusters are marked by high oxidation barriers. However, DFT analyses reveal that the attachment of organic electron-donor ligands, including trimethylphosphine, triethylphosphine, and N-ethyl-2-pyrrolidone, enhances the catalytic performance. A progressive decrease in activation barriers was observed through systematic ligation, reaching a minimum for W₆Se₈-(PEt₃)₂ at 0.16 kcal/mol. Detailed investigations, including Hirshfeld charge analysis, natural population analysis, and intrinsic reaction coordinates calculations, provide molecular-level insight into observed progressions. This study advances our understanding of catalytic mechanisms in metal chalcogenide clusters and highlights the intricate relationship between ligand-induced electronic effects and activation barriers. The results of this computational investigation open up possibilities for designing highly efficient catalysts for CO oxidation.