Theoretical Investigations of the Catalytic Role of Water in Propene Epoxidation on Gold Nanoclusters: A HydroperoxylMediated Pathway

We report a comprehensive theoretical investigation of the catalytic reaction mechanisms of propene epoxidation on gold nanoclusters using density functional theory (DFT). We have shown that water acts as a catalytic promoter for propene epoxidation on gold catalysts. Even without reducible supports, hydroperoxyl (OOH) and hydroxyl (OH) radicals are readily formed on small-size gold clusters from co-adsorbed H₂O and O₂, with energy barriers as low as 4-6 kcal/mol (1 cal = 4.186 J). Propene epoxidation occurs easily through reactions between C₃H₆ and the weakened O-O bond of the OOH radicals on the surfaces of gold clusters.