Supported AgCuCl Nanoclusters as Bimetal Catalysts for Propylene Epoxidation with Molecular Oxygen

Direct epoxidation of propylene (DEP) into propylene oxide using molecular oxygen is a promising approach due to high atom utilization and environmental sustainability. However, the absence of highly selective catalysts has been a challenge in this field. Herein, the ligand protected AgCuCl nanocluster was synthesized via a one-pot method and loaded onto BaCO3 to prepare a small size bimetal catalyst (AgCuCl/BaCO3-N2) via calcination under N2 atmosphere. A PO selectivity of 85.29% at a relatively mild temperature of 275 °C can be obtained. Characterizations revealed that AgCuCl/BaCO3-N2 with low-valence Cu+ species facilitated the formation of electrophilic oxygen species that preferentially attacked the C═C bond of propylene, resulting in the production of PO instead of attacking the C–H bond for the formation of byproduct. This study provides a clear example of using supported bimetal catalysts to achieve propylene epoxidation and offers guidance for selecting supports for supported nanoclusters as an efficient catalyst.