Pore Size Engineering Enabled Selectivity Control in Tandem Catalytic Upgrading of Cyclopentanone on Zeolite-Encapsulated Pt Nanoparticles

Selectivity control is the central challenge in the development of tandem catalytic processes. Zeolite-encapsulated nanoparticles have been shown to be an effective catalyst architecture to regulate the sequence in which reactants and intermediates are exposed to different types of active sites in tandem reactions. In this work, pore size engineering of the encapsulating zeolite matrix is demonstrated to be an effective strategy to exercise selectivity control in tandem reaction involving bulky intermediates and products. Pt nanoparticles (NPs) encapsulated in H-BEA zeolites (Pt@H-BEA) are able to catalyze a one-step conversion of biomass-derived cyclopentanone (CPO) to C-10 cyclic hydrocarbons (bicyclopentane and decalin) with a combined yield of 78%, which is the first report of accomplishing the conversion of CPO to biojet fuels in one step. In contrast, Pt NPs encapsulated in MFI zeolites with smaller micropores with similar metal and acid site densities lead to primarily cyclopentane (similar to 70%). Kinetic analysis shows that the difference in pore size between these two zeolite frameworks is the primary cause for the drastic change in selectivity, likely due to the higher energetic barriers of formation and diffusion of bulky active complex, intermediates, and products. Pt NPs supported on either H-BEA or H-ZSM-5 are unselective toward C-10 cyclic hydrocarbons in the CPO conversion, indicating the importance of the encapsulated catalyst architecture. Pt@H-BEA exhibits excellent recydability with no detectable deactivation after three regeneration cycles.