Anchoring Pd onto Sn Sites in Zeolite Framework for Baeyer–Villiger Oxidation with H₂and O₂

Incorporating precious metals into heteroatom-containing zeolites not only enhances metal dispersion but also unlocks the application potential of zeolite catalysts, facilitating the development of bifunctional catalytic systems. We successfully synthesized a bifunctional catalyst via a simple impregnation approach in which palladium (Pd) was confined within the channels of Sn-Beta zeolite. This resultant Pd@Sn-Beta catalyst enables the Baeyer–Villiger (B–V) oxidation of ketone to the corresponding lactone through the in situ generation of hydrogen peroxide (H₂O₂) from hydrogen (H₂) and oxygen (O₂). The characterizations with EPR and in situ DRIFTS confirmed the formation of^•OOH radical over Pd species, which is subsequently transformed to H₂O₂during the catalytic process. XPS and X-ray absorption fine structure analyses revealed a strong interaction between the dual active sites of Sn and Pd. The proximity of Pd and Sn active sites shortens the diffusion pathway of in situ formed H₂O₂and prevents unproductive decomposition, thereby ensuring high B–V reaction activity. Using 2-adamantanone as a substrate, a remarkable ketone conversion rate (88%) and lactone selectivity (99%) were achieved with an optimal Pd@Sn-Beta catalyst. These findings highlight the potential of heteroatom-containing zeolites as supports for developing highly dispersed metal catalysts, offering more opportunities for their catalytic applications.