Subnanometer Pt Catalysts Encapsulated in MEL Zeolite Mesocrystals for H2 Production from Methylcyclohexane Dehydrogenation

Abstract

Modulating the microenvironment of zeolite-encapsulated subnanometer metal active sites represents a frontier in the design of solid catalysts because of its marked impacts on the catalytic properties. Different from most prior works, which mainly focus on tuning the particle size and chemical composition of the encapsulated metal species, the present work focuses on the modulation of the morphology of the zeolite support to effectively stabilize subnanometer Pt clusters for H₂ production from the dehydrogenation of methylcyclohexane to toluene. By confining Pt clusters in the perpendicularly connected 10MR channels of MEL zeolite mesocrystals, we can maintain sufficient confinement of the zeolite framework to stabilize Pt clusters against sintering and to facilitate mass transport properties of the methylcyclohexane and toluene molecules, resulting in a markedly high specific H₂ production rate, excellent stability against sintering and coke deposition, and exceptionally low concentration of CH₄ impurity in the outlet H₂.