Enhanced Hydrogenation Properties of Pd Single Atom Catalysts with Atomically Dispersed Ba Sites as Electronic Promoters

Precise adjustment of the electronic structure of heterogeneous catalysts is an effective strategy to improve their catalytic properties. By preparing Pd₁Ba₁/Al₂O₃ double atom catalysts with a ball milling method as a model catalyst, we demonstrate an interfacial electronic effect of Pd species induced by Ba single atoms (SAs) as electronic promoters. The introduction of Ba SAs promotes the transfer of electrons from Ba atoms to Pd atoms, forming electron-rich Pd^δ+ species. During catalysis, Pd species with the modification of Ba SAs lower apparent activation energy and promote H₂ dissociation, which dramatically enhances the catalytic properties in several typical hydrogenation reactions under mild conditions.