Anchoring Pd onto Sn Sites in Zeolite Framework for Baeyer–Villiger Oxidation with H2 and 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 H2O2 during 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 H2O2 and 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.